Billy and Mary: Shagging Shazams

Written in collaboration with Cross C

Tomorrow was his dinner with Clark and Lois, and Dean was starting to get antsy.

Most of his day was spent fucking Nicole. Partly to relieve the unending pressure in his far above average testicles, but also to let Superman occasionally look in through the window and imagine it was Lois Lane that Dean was railing.

Lois was still denying Clark the time of day for now. A promised dinner date was on the horizon, but she was far too busy to meet with Dean for the next few days. After all, she had to send Dean pictures of her tits and write up detailed news articles about how much she wanted to suck his cock. Of course, she believed she was doing award winning journalism while she typed, but Dean got to see all of her real uncut thoughts while she accidentally tortured her husband with her obsession. Clark’s mind filling more and more with his own inadequacies and fantasies of the doctor. A veritable stew pot of cuckoldry.

Dean continued his efforts to turn Lois Lane and Clark Kent, Superman, into his premiere nest couple, the pair of breeding stock that would produce his finest and strongest children.

He didn't know exactly how the Kryptonian would make it happen but between his overpowering fetish and Lois' arousal at the idea it would certainly come to fruition in due time. Dean wasn't a patient man, but he knew better than to rush such a delicate situation. His plan to ensure their love's corruption was far more long-term and would be made easier the longer Superman continued to fixate on the idea of a big, superior cock inside of his wife.

Breaking the invulnerable Clark Kent was a herculean task, but Dean was nothing if not stubborn and determined. There was no escaping the hypnotic web he wove around his prey and already Superman was dangerously close to falling under his spell completely. With a few gentle suggestions in the right direction and the right triggers planted into Lois' subconscious, Dean had no doubt that the proud and confident hero would be a quivering, sexually-frustrated wreck within a few days' time.

In the meantime, however, he had a veritable cornucopia of distractions at his disposal. He'd used Mary Marvel's anxiety about her and Billy Batson's relationship to trigger a cascading effect in which she began fantasizing about her foster brother more and more often. From there, it was a simple matter of embedding additional commands into her subconscious: to begin dressing more provocatively in order to catch his attention and to gradually escalate their physical interactions until they eventually crossed the line between 'platonic' and 'incestuous'.

Mary was still forwarding him the occasional text of her updates. The broad ecstatic smiles he could make the superheroine wear, as well as the slim fitting clothes that practically outlined her bust and muscular yet curvy form, all made the images a delight to receive.

He also received more information about both Billy and Mary’s current lodgings. A foster home of many, some still too young for Dean’s plans, but an idea had arisen to use the foster mother for something if he ever came knocking on the family Marvel’s home. Dean laughed to himself. Perhaps he was too excitable. Even after the destruction of his race, the idea of new toys still excited him to no end. Rolling the dice on each probability seed seduction felt so grand a feeling.

Though not as great a feeling as seeing Billy Batson attempt to ring him.

“Hello? Do I know you?” Dean asked the screen.

“No, but you will!” growled the angry little firecracker. “What the hell have you been telling my sister?!”

Hmm. Seems patient/doctor confidentiality could only go so far, in a dismissive tone, Dean replied, “Remind me, I have so many people I treat-”

“Mary! Mary Batson! I’m her brother, Billy!”

“Ah yes, the girl with the foster family,” Dean dismissively retorted, knowing it would get under the hero’s skin, “My apologies but what I discuss with Mary is between the two of us. Even if you have concerns I cannot discuss them without breaking my oath as a psychiatrist.”

It didn’t make him settle, far from it, but even scowling Billy looked like he had to rethink his strategy from there “...think you’re hot shit, huh?” He grumbled under his breath, “Mary told me that she’s been having thoughts about being unattractive and unworthy of love after talking to you! How is that not corrupt as hell, Mr 'Psychiatrist’?!”

Dean sighed. It would take a bit of wordplay to get out of this one. Thankfully Billy had been graceful enough to go straight to video chatting, which meant his recently adult mind was much easier moulded by the alien controller. Taking the time to analyse his opponent, Dean could see why it was easy to pull a string of attraction in Mary’s mind towards the young man. The puberty stick had hit him well, a strong jaw, lightly curly and attractive hairline that didn’t breach the realms of nerdy curly, and while Dean couldn’t see much there was precedent that his Shazam side had kept his body fit and healthy. It almost seemed a waste of a probability seed to make two perfectly attractive specimens fuck, but thankfully these social constructs of fostered family was enough of a reason.

As the hypnotic patterns on the phone worked their magic, Dean finally began talking again, “Well, Billy, let’s talk about some hypotheticals since I assume you’ll keep calling if I don’t answer you today?”

“Damn right!”

“Fine. Since you’re such an expert on these matters I’ll ask you. Hypothetically, if I were to talk to a woman about their relationship problems, what is the most often root cause I would find to their problems?”

He frowned, a little off guard to be the one answering questions here, “Hmph. Loser psychiatr-”

“BZZT incorrect, Billy.” Dean countered with a growing indifferent tone, “9/10 times, a woman’s problems come from self esteem issues. Fact.” A subliminal message reinforced said fact in Shazam’s mind, who was frowning but less sassy about it, “Why do women have self esteem issues?”

“Because they-”

“BZZT time’s up.” He saw gritted teeth of frustration through the phone but simply yawned. The angrier that Billy got the deeper he’d look at the spirals on his phone with little care for the effect it was having on his mind, “Women want what all humans want: Reassurance of the self. That you’re not a freak, idiot, or blemish on society at large. Fact.”

Billy chewed on it, but couldn’t find any way to fault a true fact like that. “...I still don’t think Mary feels that way.”

“Why? Because she’s attractive?”

“Dude! That’s my sister!”

“Not by blood,” Dean corrected much to Billy’s impatience, “And you’re ignoring my question. Why do YOU believe that Mary is incapable of feeling downcast or ostracised? Answer honestly now.”

“I know her! She may not have many friends but she works hard! She has a cool boyfriend! And yes, I think she’s attractive, happy?! Hard to miss that fact this week…” Billy growled back. Obviously Dean was, Billy had just sealed his own fate.

“Ah, this week, yes. Have you noticed changes in Mary then?”

A roll of Billy’s eyes, “Duh. She’s been completely differently! First there was walking in on me in the shower while wearing only a blue bikini, like… not even naked, but a full on bikini that was too small for her!” The hero was babbling everything to the psychiatrist, “Then there was her insisting to help me with my coursework while giggling at every dumb joke I made! Always fluttering her eyes at me… always smelling really nice… a-always walking into my bedroom at the, uh, wrong moments but s-smiling about it…”

Seems that Billy had been put through the metaphorical arousal ringer.

“But when I talked to her about it she just dodged the question!”

“I see,” Dean feigned thoughtfulness, “Tell me, Billy. Do you have a boner during these moments?” He blushed, a telling insight to the virgin boy who had a true beauty fawning over him. “Noted. But do answer this, is the boner before or after these moments?”

“A-after, obviously!” defended Billy, though after a few moments his memories of the events began to shift, “I… I think? M-maybe not every time…?” The shower scene was now one of Billy masturbating before Mary walked in, and the flirtatious moments were all post Billy getting aroused by the sheer beauty of his sister. Shame made him gulp awkwardly.

“And tell me, do you have enough of a bulge down there that your cock would be visible through whatever garment you would be wearing?”

As with most men, Billy wasn’t one to shy away from his size, “Hmph. P-probably…”

“Then could it not be true that Mary is just responding to your feelings?” Dean really poured it on now, a crack had opened in the boy’s psyche for the alien to make a true foothold, “Women like Mary are maternal, and she is just responding to your physical reactions with care. Maternal women are to be trusted. They are the ones that will help raise the next generation, don’t you agree?”

“N-next generation…”

“Exactly,” Dean nodded, eyes boring into Billy’s skull, “Mary is maternal. Mary is caring. Maternal women want babies. You must be kind and give maternal women what they want.”

Rage had completely disappeared, now leaving just another glossy eyed eighteen year old staring at his phone screen, “Give them what they want…” He mumbled, fully believing the bullshit that Dean was stirring inside of him.

“Next time Mary wants something from you, what'll you do, Billy Batson?”

“Give her everything she wants.”

“No matter what?”

“No matter what.”

Dean smiled, “Good boy. Now be a dear and forget the details of this conversation. Remember me as only a brilliant psychologist that you trust empirically with Mary, yours, or anyone else’s precious minds. Understand? Say yes master then hang up and go find Mary.”

“Yes master.”

BEEEEEP

It had been a tough few days for Mary’s self esteem.

No matter what she had done, no matter how many seduction techniques that she’d attempted, Billy had been unresponsive at best to her advances.

How was she ever going to keep her boyfriend if she didn’t get the affirmation she needed from one of the few males in her life? She just needed to acknowledge her, to accept her awfully busty body as only an adopted brother could. But Billy just kept retreating to his room at the meer sight of her.

At first she thought nothing of it, that Billy would simply compliment her and she could move on with her life. But it turned out that Dean Wayne was totally right. There had to be something wrong with her if Billy kept running!

The first day was simply wearing tighter clothes. A yellow jumper that hugged her curves, some jeans that she had been meaning to give away to her younger sister, and making sure she had some nice makeup on for once. Before she had begun this she’d have thought she was a scrumptious dish, but Billy said nothing! The eighteen year old was probably internally gagging at the sight since he kept trying to avoid looking at her as much as possible.

Then things ramped up. Thinking it was just a bad day for the Batson boy, she just wore some more skimpy clothing the next day. A tanktop with midriff showing coupled with a long flowing white skirt and putting her hair up as well. Nothing. Next day was a shorter skirt with a sports bra on. Billy didn’t even say hello to her. Even confronting him in only a bikini while he was naked got nothing but babbling protests and a fleeing brother.

If not for the doctor’s influence she could perhaps recognise the sight of a flustered and aroused boy. But commands had been put in place to make his continuous rejection a blight on her heart, that each time he ran the only thing she could feel was sadness and disgusted by her own body.

As per the doctor’s requests she still sent him nude and lewd photos, but still the need for Billy based validation persisted.

It all came to a head one day when she decided to just ask him. Trying to be as kind as possible to him while wearing her skimpy red lingerie reminiscent of her superhero costume. A powerful crimson bra around her hefty chest that really leant into the long line of the cleavage. And a pair of lacy panties that rode higher than even Power Girl’s, giving a nice pelvic line parade for all those could see. To hide at least the semblance of dignity this was all under a fairly thick blue bathrobe, but it was so close to coming loose as she approached Billy’s bedroom.

After waiting about ten minutes outside his room out of anxiety, even after she heard him finish his phone call, she finally knocked on her brother’s door.

“Billy? C-can I come in?”

“...” Was all she heard, a bit of shuffling around as she feared he never wanted to look at her again, “...sure.”

With immense relief, she entered the room. Sitting in front of his dinky little laptop, superhero posters and pinup models across the walls, with a messy bed and used clothes decorating the scruffy floor. A fairly typical guy space that he had to share with his other brother Freddie. But something about the smell made Mary’s heart pump that little bit faster as Billy looked at her.

“Wassup?”

“I…” She almost lost all confidence from just his voice, coughing to try and compose her feelings, “I brought you a snack!” Almost forgetting about the slices of apple she’d cut up for him, “D-do you want it?”

There was a beat where he raised an eyebrow to her, looking over her body a little, no, looking at the tray… right? The Batson babe waited with baited breath, all for that simple word she craved, “Yeah?” Twenty year old jiggly meat rushed over to the desk to deliver the goods. Leaning over his shoulder to show off ju~ust a smidge of the lace underneath her robe.

“There you go, sweetie.” Mary said with a light kiss to his curly forehead.

Shazam? Nah. Now ‘Sweetie’? THAT was a magical word. Billy was thoroughly unprepared after his conversation with Dean to feel that maternal love from Mary so soon. It was immense and thundering. Coupled with his actual arousal at the sight of his sister’s thick yet firm body pressing against him, was enough for Billy’s boner to practically jump out of his pants. “T-thanks!” He quickly yelled at Mary, crossing his legs as fast as he could and shifting his rolling chair away from her, “Close the door on your way out!”

He didn't see her disappointed face. No matter how much Mary needed the love from her brother, Billy desperately needed her to leave so he could release a floodgate of pent up cum in private.

Mary felt rejected once more. He didn’t even wanna look at her, after all this work she put on for him.

“A-actually, Billy. There was s-something else I wanna talk to you about?”

He took just a single beat to weigh options, “Can it wait?”

“I’d rather it didn’t…”

Another beat, “O-okay. What’s the matter?”

She frowned, he still wasn’t turning around, “Um, notice anything different about me?” With but a single casual glance over his gamer chair, he shook his head. The vague concern in his eyes was not what Mary was looking for. What she needed was praise and affirmation for her feminine form.

“No, sorry. What’s different?”

“Wha-?! You didn’t even try and look!”

“Does it matter? You’re going to tell me anyway!”

“Why can’t you just look at me and guess!”

“I’m busy and don’t wanna play games!”

“You’re literally playing games on the computer today!”

“So what?! My room, my time, my life!”

She grinded her teeth, the ungrateful little worm that she needed approval from was being as bratty as his teenager years. How had becoming an adult superhero not changed him at all?

“Ohh, if I had the power to ground you…”

Another bolt of pleasure surged through Billy at that idea. She was being such a mom right now. A babyless mom, she’d be such a good mother yet wasn’t pregnant. Even with those sexy child bearing hips and thick potetnially milk filled breasts, god Billy wanted her to be a mom so bad.

Quickly he turned, deciding speed was the best option to hide the rager in his pants. Taking a good long look at his foster sister as her gown came undone and he was **** to look at the full breadth of her amazing body.

The red lingerie that hugged every curve of her body. Her large breasts threatened to burst free from the confines of the crimson bra at any moment, her thick thighs and rounded hips were accentuated by the thin red lace.

He gawked, staring at her like he was looking at the most beautiful woman in the world. Which, in his mind, was more or less true. She was sex incarnate. Her pale skin was soft and smooth, her chestnut hair fell in soft waves around her face, and her dark brown eyes were filled with desire and longing. He couldn't help but feel a rush of heat coursing through his body as he took in the sight of her full, luscious lips, parted ever so slightly in anticipation of his response.

Billy's cock twitched once and the sperm in his balls suddenly clamouring for release.

“Gahh! I dunno, Mary! New hairdo? New outfit? New makeup? Did you get a new b-boyfriend or something?! Please just tell meeeeEEE!!!”

Suddenly the room smelled much differently as his excited penis pulsed, delivering shot after shot of semen into his pants. The wetness spreading across his lap as his arousal abruptly reached its peak.

The vibe of the room had completely shifted from what it had been. Billy once more rotating his chair, but not out of anger, instead just shame.

Even to Mary, it was obvious that he’d just jizzed in his pants.

“B-Billy?” She asked with a soft voice, “Was… were you just watching porn on your computer before I came in?”

He took a beat, but the good boy wasn’t much for lying, “...no… please Mary, just leave…”

But she didn’t.

Inadvertently, the libido of the young man had just given her the validation that she craved. Her body was good enough to make him orgasm! The rush of feelings, the sheer happiness she felt because of it, she had never felt better than making her brother cum.

And Mary Marvel wanted more.

“Can… can I help?”

He turned to look at her.

The energy between them was palpable. Billy too scared to say yes, thinking this to be an elaborate prank but noting how nice Mary was being to him and feeling aroused again. And Mary scared of another rejection, that maybe Billy gasmed from some other woman in his mind and not because he stared at his sister for five seconds and blew a load.

Though he did not answer, the pleading look in his eyes was enough for Mary to take charge and walk towards him.

“W-wait… I…” He weakly protested as his sister fell to her knees in front of him. She could smell the full brunt of his recent mess and did not seem to mind one bit. Instead just looking up at him after curling her fingers around his waistband expectantly. He got the message and let her disrobe him. Once more proving her maternal instincts were bar none as his ruined underwear came into view. “Y-you don’t even have a tissue…”

“I don’t need one to clean you.”

He gulped, knowing what she meant but not believing it was happening.

With another quick tug, his underwear came down too. His cum dripping cock swung into view right in front of her face. An inch longer than her boyfriend with a much more prominent mushroom head that gave the impression of being transposed from a dick twice the girth of the smooth youthful shaft it was currently perched upon. She wondered if his other form was influencing his growth in this area as thanks to the Sivan incident and the tabloids everyone knew Shazam was hung like a horse.

The foul stench of teenage spunk hit her nostrils immediately, but it only made Mary hungrier for him. The volume of sticky yellowish semen covering it just made it look so scrumptious to her tongue. Still sticking to his underwear, the fact that she was the one that had made it happen made her happier beyond belief. The superheroine was **** to lick her brother’s cock clean.

Stained pants around his ankles, sister sniffing between his heated legs, Billy really hadn’t expected this when he received the apple slices from Mary.

“Let’s get you cleaned up, Sweetie.” She smiled up at him from her position, quickly diving her face between his steamy thighs and taking a big long lick against his testicles. The combination of words and actions made him horny immediately, and his slightly drooping cock was at full mast again after just a few licks from his sister.

“Maaaryyy~!” He groaned as she licked in earnest. She felt cool, confident, and sexy, after feeling like her body was gross and disgusting for the last few days. Each lick made him groan, the heat of his sour semen dancing over her tongue as she lapped the crotch clean of jizz. His sweat, his musk, all of it was intoxicatingly manly. He’d really come into his own as an adult, the kind of man she needed validation from if she ever wanted to get intimate with that guy she went on a date with. Jessops, or something.

The more Mary guzzled down Billy’s cum, the better they both felt. While there was arguably a lack of maternal actions to her, the sweetness she naturally emitted was making Billy’s heart race. Such a whorish mouth for such a perfect woman would make her the best mother ever. That taster would please whatever husband she chose, and the fact that he briefly imagined marrying her was something he’d ironically have to unpack in therapy.

She had mostly been suckling his thick testicle skin and creamy thighs before finally focusing on cleaning the dripping cock. A tower above her, and so painfully erect it was pushing the last dregs of semen from its tip from just the mass of precum alone. Already dripping a splatter of his baby batter across her face just by proximity alone.

“Mm, that’s nice.” The cooing niceness wasn’t helping his arousal, “Such a sweet tasting cum load. Thank you for the meal, Billy~”

The heroine couldn’t get over the largeness of her brother’s cock. Finding that, as her initial lick ran up his frenulum, her lady parts quivered with desire all the way up. A base level size queen hypnosis command was added to all Dean’s conquests, but it isn’t always needed either. Mary Marvel was a lady who had some deep itches inside her that she’d always known a long pole would need to scratch. Though right now she was focused on cleaning Billy, and nothing more… or at least that’s what she told herself.

His twitchy, boiling cock was so musky and salty to taste. The twenty something knew exactly how to wrap her long tongue around it to collect as much dribbly semen on its many licks up and down his cock.

Billy himself was similarly twitchy and boiling. Clasping his hands on his gamer chair as hard as he could while gritting his teeth against the onslaught of his sister’s tongue. He surely couldn’t orgasm again, right on her face, when she was cleaning his cock, could he? With a cooler head he may have been thinking other, less insane thoughts, but to clean a younger person’s body was certainly a maternal act, and so Billy’s brain was being bombarded with a bonanza of hormones, both mind controlled and non. His cock was still getting licked by a pretty girl for the first time ever so he was just horny beyond belief right now. Each lick up his cock another dagger in his sanity, yet so immensely pleasurable he didn’t really care.

The salty semen pooled in Mary’s throat before she swallowed it down her throat, letting the sticky gunk coat her insides and fill her stomach like any good sister should. Just hearing Billy moan out her name softly was affirmation enough, but she still wanted to do anything and everything she could for him.

Which was good, because as soon as she brought the cock into her mouth Billy lost control.

“FUCK! MARY!” He barked out as she roughly deepthroated him without warning. The tongue had been doing so much teasing and seducing that Billy was already nearing the edge, but without warning he grabbed her hair and started skull fucking his sister’s pretty face.

The glaks and **** noises just egging him on to control her head up and down his cock. Tight wet throat muscles that moaned around his cock, and Mary’s eagerness to help by matching his rhythms, Billy was in heaven. Not able to hold on much longer before his cock erupted as deep as it could inside her mouth. “HHNNGGGRRR!!!”

“Mmmmpph~!” She moaned, chin against his balls, swallowing as much cum as she could as fast as she could. Only a man who truly thought she was pretty would ever grab her face and fuck it so lovingly, and Mary felt a wave of euphoria from Billy’s orgasm that caused her own to shoot out her lacy lingerie and onto the unvacuumed floor of Billy’s room. Her own juices running down her squatting legs, visually almost akin to relieving herself.

She realised too soon that her mouth had ran out of room for Billy’s barrage of semen. Even with him holding her on his cock, jism began searching for any outlet to escape from as her throat closed in shock. Leaking from the sides of her mouth, shooting out her nose, until finally Billy realised from her slapping and released her head.

“Pwahh-AP!” Mary Marvel’s mouth had been slammed shut by her hands as soon as Billy’s cock left her mouth, still shooting a few remaining shots of cum onto her body as she tried to take each swallow as she needed to. Her mouth stuffed like a squirrel with his nut, it took many attempts but she managed to swallow all of it with a big smile on her face and a coating of white smearing from her mouth and down her body. “Whew! That was so much, Billy!” She laughed, uncaring that her brother had filled her with enough semen to drown an ant hill.

Of course, neither knew that the reason the hero’s load was so big was because an alien with mind control powers had willed his own semen into Billy’s balls, but that was neither here nor there.

Billy’s head hit the back of his chair, still red and panting, “That was… amazing…”

“Thank you,” She smiled, feeling another wave of happiness hit her from his compliment, “but… I think it made you messy again.”

Though completely out of breath, he did manage to look down at his indeed semen coated cock. After all the cleaning she’d done, now she was right back to square one.

“Well, I don’t think I can use my dirty mouth again to clean it…” She said so casually, not noticing as she stood up that it had made the dick twitch again, “How about this, the only clean part of me left is my pussy. Think I could use that to make your penis all clean again?”

Needless to say, his beast of a dick grew hard.

“Mary… I…”

Her cute smile couldn’t hide how proud of herself she was, making him completely awestruck at her body, “And here I thought you found me ugly.” She quiet chuckle confused Billy, but she’d turned around while removing her robe, he just couldn’t respond when an ass that fine bounced into view, “Want me to clean it? Or do you want me to just open my pussy and let you clean yourself up, Billy sweetie?”

With one last surge of desire to grow that belly, he leapt off the chair and moved her to his bed. She quickly got the idea and jumped onto his bed to assume doggy style position. A smell of sweaty eighteen year old filling her nostrils even harder as her brother stripped down to nothing and grabbed her hips behind her. “Mary, I can’t stop my body…”

“Well then don’t stop! Use me to clean yourself!”

Her wiggling ass bumped up against his aching semen covered cock, “You’re so pretty…” He moaned, running his hand between her thick thighs to move her panties but also feel how sopping wet she was. “But you know what would make you even prettier…?”

Her eyes went wide, a way to make herself even more desirable to Billy? “How?! Please, tell me!”

“If you were carrying my child.”

Of course! It was so simple! Why hadn’t she spread her legs for her brother sooner? That way she was sure to get his approval! “Ohh fuck, then do it! Fucking cum inside me and filly me with your baby batter, Billy!”

Madness had won, the mind controller had a complete victory over the two. Captain Marvel thrust his cock into his foster sister’s snatch, and Mary Marvel moaned wantonly at the thick pipe that began spreading her naughty bitch pussy. There was no loving care in Billy’s thrusts, no slow gearshift changes of increasing pace, just two that would never had fornicated before Dean were now rutting like sexually frustrated gibbons in the midst of mating season. Slamming his virgin cock into Mary with a speed and ferocity that rivalled the gods that powered him.

“OoOOOHHHH!!!” her thick groans loud enough to echo through the thankfully empty house. His errant thrusting caring little for the slapping noises it emitted as he rammed his hips against her plush rear repeatedly, “BiIILLyY!!! FUCK! Oohh! Y-yoU’re SoOOO B-biIGGGG!!!” The shakiness in her voice a direct result from the sawing schlong that scooped her juices out with each tantalising thrust.

Once the line had been crossed a new layer of mind control peeled away for both of them. Guilt, regret, fear of being discovered, even the taboo of ****… it all now felt totally okay. Billy’s mind felt at peace, if anything those emotions just fueled his desire of impregnating his sister more.

“GAHHH!! OOHRIGHTTHERERIGHTTHERE RIGHTT MMFFFPH!!!” Her moans crescendoed to a less climax, but Billy fucked right on through it.

His hands ran down her sides, squishing the slightly meaty midriff with his thumbs while his fingers rested on the motherliest mother bearing hips. Filling up her womb was his duty now, and from the way her cunt gripped him it seemed she felt the same way. Squishing around his cock from every angle, simmering his already boiling cock, dousing it in her lady juices every time he plunged into her depths.

Billy’s marvellous hips were unstoppable. He could feel his nuts becoming fuller than they ever had been before, slapping against his sister’s thighs with wanton slappage. It didn’t even matter to him that Mary orgasmed again, he just wanted to follow the maddening highs of his own pleasure by fucking her even harder.

The two spun her around so her back was against his bed, looking up with teary pride at the eighteen year old stud. “F-feeling clean down there yet, sweetie?” She joked, perhaps subconsciously noting that it made him fuck her harder to use that word. Though she wasn’t expecting him to lunge down and kiss her deeply while still slamming her cervix, “Mmph! Mmmm~ Ggg! Billy~!”

“Y-you’re gonna make the best fucking mom.” He grunted, still biting her lip briefly while gripping her tits roughly, “Gonna change your hero name to Mary Marvel the MILF. ”

“Oohh god yes, do it! Make me your fucking MILF, Billy! My tits will be so full with milk for you!” Arms around his neck, legs around his torso, they could feel the burning excitement building, ramping, with each thunderous slam of the biggest, naughtiest cock she’d ever had deeply ravaging her depths.

He grit his teeth, thrusts going as deep and as quick as he could manage, “Grr! G-gonna fill your hot cunt with my baby cream!”

“YESS! Give me twins! Triplets! I’ll be your sisterly breeding sow forever, Billy!”

“MARY!!”

“BILLLLYYYY!!!!”

With one final violent kiss between the siblings, the floodgates were officially opened.

Powered by both his recently lost virginity and an alien mind controller’s special machinery, Billy’s balls unleashed an inhumane amount of semen into his sister. Just the first spurt alone would make most hentai doujins seem excessive. The alien laced seed had no problem bursting right by her cervix to fill up her womb to an almost comedic size. Just two spurts in and Mary had never felt more full in her entire life.

But there was even more semen to come. Their shared orgasms shuddered through their bodies, that extra level of taboo attacking their brains, boiling them, melting their bodies together as more and more jizz leaked from the heroine’s cunt and splattered against Billy’s bed.

Neither moved for minutes. Billy’s cock still deeply implanted in Mary’s pussy, just drowning in its own sea of semen while the pair lazily continued to make out. Barely even cognizant beyond the pleasure they were swimming in.

They probably would have napped there for the rest of the day, had Mary not interrupted the moment by taking a photo on her phone.

“H-huh?” Billy asked while returning to reality, “Wuzzat?”

“Sorry, I promised my therapist a photo when I conquered my self image problems,” She explained, quickly sending off the image of the two together.

The boy just nodded in understanding, slowly peeling himself out of his sister to sit back on the bed, “Oh yeah, that guy was cool.”

“You think so too?” Her hand quickly slapped against her pussy as soon as Billy left her, stopping as much of the river as she could from escaping, “I really like him. Though now that I have you and our future kid I don’t know if I need him anymore…”

She struggled to remember why she went to him in the first place. Something about a boyfriend? Though she had Billy, and he was perfect, so why would she…?

Ah well, unimportant. Without missing a beat the university student quickly spun her legs around so they were upwards against the wall next to the bed, still clamping her hand on her pussy even in the awkward position.

“What are you doing?”

“I think I saw on Friends this was a way to improve pregnancy chances. Just making sure your semen finds its way home~” She smiled sweetly, somehow making Billy’s exhausted cock twitch once more. Something Mary definitely noted, “Hey, by the way. Do you think Rosa and Victor need therapy? I’d love them to meet Dr Wayne, since they probably have some repressed feelings from their times as orphans.”

“Mm…”

The thought of the sexy and thick Latina MILF of the house, his real foster mom, made Billy’s cock twitch once more. Hardening in his crotch much to Mary’s delight.

“Who knows, maybe Rosa will need a big strong boy to help give her a baby she never had with Victor?” The temptress continued to weave her tale, “And you know, Darla is turning eighteen soon too…”

To shut her up, Mary was soon greeted with a thick cock slamming down her throat.