You pitch the idea to Olivia.

I woke up when my alarm did, blinking sleep from my bleary eyes. I looked around and realized I was in bed, next to my naked girlfriend, with the ability to modify her or myself in any way I pleased. Life was good. Stacey stirred besides me. "You cheated," she grumbled. "You took way more than two." I patted her on the shoulder. "I'm sorry, but I couldn't help myself." Stacey rolled over to face me. "Well, I guess I can understand that. But what are we going to do when Olivia takes a shower-" she paused as in the distance, we heard the water in the bathroom turn on.

"Nothing," I told her. "We pretend like everything is normal and wait for her to bring it up." Stacey nodded. "And then?"I smiled. You see, this had all been part of my plan. I did that not only to get back at Stacey, but also to seduce Olivia. I told her my plan. Stacey looked at with skepticism. "Well, if you think it will work, I guess I'm done." She sighed. "But you owe me." I looked away. "Well, I suppose. But I was just thinking- could we maybe stop that, at least for a while. With Olivia, we need to be a united front." Stacey nodded. "That seems fair." She sighed. "Also, should we tell Olivia about the marker?" I thought about it. "Maybe later. For now, let's keep it to ourselves. We should say that it's our power, not the marker."

Stacey nodded. "Okay." The conversation died down for a minute as we both thought about what we were going to do. Then after a second, Stacey mused, "I really wish we knew the limits of the marker though." I nodded. "Yeah, that would be helpful." Then I remembered I was magic. "Oh, duh." I leaned over, grabbed the marker and rolled over towards Stacey. "Hold still," I told her. "Hey!" She protested. "I thought-" I shushed her. "This isn't about that."

On her arm I wrote, "Knows the limits of the marker". Stacey's eyes widened for a second. Then she turned and looked at me. "None." I stared. "Really?" She kept a straight face for a second, then giggled. "No, silly. But their might as well not be any." She held up a hand. "1, the Marker can only change living creatures, no objects. 2, the marker's writing can be erased by water with soap or similar scrubbing agents. 3, unless that writing is underlined, in which case it is permanent unless crossed out. 4, crossing something out automatically nullifies it and 5, new writing trumps old writing."

Permanent writing? That sounds interesting. You file that thought away for later. Then, noticing the time, you both got ready. You almost went to take a shower, but then remembered you wrote, "Clean" on your body, so decided it was fine. You got dressed in your lounge wear, but held off on your shirt. "Make sure you only write what I told you." Stacey chuckled. "I'm not that much of a trickster, Finn." She scribbled something on your back. You pulled your shirt down and tested it out. The marker suddenly yanked itself out of Stacey's hand, floating up towards the ceiling. You hold it there, making it levitate. You couldn't see it, of course, but Stacey had written, "Telekinesis" on your back. "What do you want?" you ask Stacey as she is snapping on a bra. "Uh, I don't know. Something that will convince Olivia?" You think about it, then move the marker with your mind over to your hand. You then walk over to Stacey and write, "Can control hair and skin color". Stacey turned around, then tossing her short hair back, it changed from warm brown to strawberry blonde. "You like?" You asked, wiggling her hips and thrusting her lingerie-wrapped chest toward you. You felt your morning wood become a normal erection. "Yes." You smiled. "But I prefer redheads who are more red than pink." In response, Stacey turned her hair bubblegum pink.

You both laughed, then she changed herself back and you went outside to the kitchen. You started making bacon and Stacey started making pancakes. Soon breakfast was ready and you sat down at the table, waiting for Olivia. It took her a bit longer to come out. For a moment there, you were worried she wasn't going to show up at all. But dutifully, she did, though a few minutes later than usual. You gestured to her. "Come on, Olivia. Your pancakes are getting cold." Olivia just stared at you for a moment. "What are you two up to? Is this a bribe?" Stacey cocked her head. "For what?" Olivia's expression transformed into one of pure shock, her mouth dropping open. "For what?" She asked incredulously. "You know what! You guys were fucking on the couch right besides me last night, and I didn't care. How? What? Huh?" You gestured for her to sit down. "Olivia, please, have breakfast. I can explain."

Olivia sat down. "Go ahead." She crossed her arms. You give an exaggerated sigh. "We're wizards." Olivia's shocked expression returned. "You see," you continue. "Me and Stacey have the power to use magic. We can use our powers to change ourselves and the people around us." You point at a piece of bacon in front of you and make it float through the air, wriggling like a seasnake swimming through the water. The bacon lands on Olivia's plate. At this point, Olivia has gone pale. "Magic is real?" Stacey nods. "We know it's a lot to take in." Olivia nods, then pokes the bacon with her fork. "Eating this won't turn me into a frog, will it?" You laugh good-naturedly. "We'd never hurt you, Olivia. It's just bacon." Olivia ate it, albeit a bit reluctantly. "Anyway," you say, "Last night me and Stacey were horny, but you had just gotten home. So we ensorcelled you to make you think there was nothing wrong with couples having sex in front of other people." Stacey piped in. "When you took a shower this morning, that broke the charm. You know how running water stops ghosts? It's like that."

Olivia didn't say anything for a long time. "So, you guys can do anything?" You went to answer 'Yes', but Stacey grabbed your arm beneath the table. "Sadly, no." She said. "We do have limits. For example, we can only affect people, and only people who consent to be affected." You look over at Stacey, but she sends you a look that seems to say, 'Trust me'. You do trust her, so you run with it. "And because of that, we realized something. You must be really pent up, otherwise you would have never consented to my sex charm." Olivia flushed. "Whoa whoa, what?" Stacey chuckles. "He means the spell, Liv. You see, we chose to specialize in a certain type of magic. We're Sex Magicians. Besides a few generalist spells, we mostly only know spells relating to sex." You smile to yourself. You get where's she going now. "Being horny, or having suppressed sexual drive are both ways of consenting to a sex charm," you say to Olivia. "Tell me, when was the last time you got some?" Olivia colored bright red again. "That's none of your business." You cover your mouth. "Oh, sorry. You're right." You fold your hands on the table and give her a serious look. "On a more serious note, I want to apologize. Even if you did subconsciously consent, I shouldn't have enchanted you without your permission. So, we'd like to make it up to you."

Stacey came in now. "If you want, we will use our sex magic to help you fulfill any fantasy you want to. And I assure you, whatever you want, we can do it. Our power on matters erotic is vast." To punctuate her statement, Stacey winked at Olivia and turned her hair white, then back. Olivia watched that in shock, then began eating, not responding for a few minutes. You sat in silence, wondering if you had overplayed your hand. What would you do if she refused, or freaked out? Finally, after what seemed like an eternity, Olivia spoke up. "Well, I, I guess one time wouldn't hurt." You resisted the urge to smile like a maniac. Got her. Stacey smiled subtly to you, then looked back at Olivia. "So, what do you want to do?"

Olivia looked between you two, then glanced down at her pancakes. "Well, this is a bit weird, but here goes. I'm no virgin. I've been around and played around with a few guys. There was even a girl once- though I was far too drunk to be making good decisions at the time." She cleared her throat, then went on. "But a lot of the guys I got with were first-timers, or just kind of inexperienced. Mostly, it was lackluster to say the least. There was this one time though," Olivia lifted her head, her eyes distant as she recalled something pleasant. She looked back at you two and continued, "He was an older guy I met at a bar. Not old, but definitely in his late 30s, maybe 40s? Anyway, he was a tattooed tough guy who asked if I wanted a boy or a man. When I said the latter, he took me back to his hotel room and choked me, then pounded me so hard that I couldn't sit right the next day." Olivia's face bright-red by the time she finished. "So, I don't really care what you guys do specifically, just, feel free to use me to enjoy yourselves." There was a silence, as you and Stacey both absorbed Olivia had said. The awkwardness got to her first. "Well, would you look at that?" She muttered. "I've got to get to work. I'll see you guys later then. And if you think that's weird, just forget I said anything." She smiled awkwardly then stood up and left.

Stacey and you both kept your silence as she pulled on her shoes and we heard the front door open then close. Once she was gone, Stacey pumped her fist. "Yes." You arched an eyebrow at her. "Come on, this is perfect," Stacey said. "Isn't this what you wanted?" You shrug. "I just wish you wouldn't be so enthusiastic." In response, Stacey smacks your arm. "Don't be such a baby." You eat a little more, then Stacey asked, "So, what are we going to do?" You think about it. "We need to do something small, so she won't get scared off. Ease her into it." Stacey groaned at that. "Fine, but we're not going to just do normal stuff." You nod. "Agreed- we have a reputation to uphold as 'Sex wizards' or whatever. I'm just saying, nothing too strange. No turning people into sex toys or switching sex." Stacey frowned. "Half of that is only stuff you're guilty of." You ignore her. "So, we should set some boundaries for the marker. For this time." Stacey tapped her fingers on the table. "How about we make a list of things we'll write ahead of time? So there won't be any surprises." You smile. "That kind of kills the spontaneity, doesn't it?" In response, Stacey smacks you on the arm again. "We're making a list or we're not. And if we're not, first chance I get I'm going to use the marker to turn your fingers into tiny cocks." You stand up and begin searching the kitchen for a piece of paper and a pen. "What do you want to start with?"

Hours later, you are sitting at the table, waiting for Olivia. Stacey was in the bedroom, getting dressed for the evening. You're trying to remain calm, but inside you're actually quite nervous. This is your first time being with two women at once. You don't want to disappoint them. And while the marker could help, you and Stacey made plans about how it was to be used. Plus, wasn't that cheating you thought to yourself? It would hardly benefit your self-confidence if you had to rely on magic. So you just grit your teeth and pray it goes well.

Just then, you hear the sound of keys turning in the lock. "She's coming," you call to Stacey. Stacey yells back, "I'm ready when you are!" You nod. The door opens and Olivia walks in, wearing a sensible black jacket with matching skirt, wearing a modest white blouse underneath. You study her body as she walks in, from her flab-enhanced curves to her pillowy thighs and large, bountiful bosom, she looks delicious, even covered up and dressed sensibly. "Hi Finn," she says nervously. "What are you doing here? Are you waiting for delivery?" You stand up and gesture to the door to your bedroom. "We decided we liked what we heard, Olivia. We want you to come join us. We'll do precisely as you asked, in our own special way." You resist the urge to swallow and do your best to look confident. Here it is, the moment of truth. You put on a smug smile. "Or are you too scared to take what you really want?"

Olivia swallows hard. But she sets her bag down on the table. "I, I want to." She marches forward, moving past you, heading for the door to you and Stacey's bedroom. She opens the door and steps inside. You follow after her.

You open the door to your bedroom to find Stacey sitting on the bed, wearing a light blue, transparent negligee over a white bra and matching panties. You're stunned for a moment- you've never seen that outfit before. Then you realize that's not the only thing different. Stacey is some much more, fierce. She is staring at the two of you hungrily, like she's a ravenous wolf about to devour you. Instantly, you're rock hard. Olivia notices the hunger in Stacey's eyes too. "Come here, Liv," Stacey orders. You shut the door behind the two of you as Olivia walks over to the bed. Stacey gestures to the ground before it. "Take off your clothes, and kneel." Olivia stops. "What?" Stacey is on her knees on the bed, but from her posture, she looks like the one in command, like a sultana who has risen off her pillow. "You wanted us to give you pleasure, right? Well, you must ask for it."

Olivia turns and looks at you. You nod your head. "Sorry, but those are the rules." You gesture to the door. In response, Olivia turns back and swallows hard. She then begins disrobing. She takes off her jacket and then her shirt, then pulls down her skirt. Soon her voluminous breasts are revealed, contained only by a fancy black bra. Her bottom is covered as well, but this time by a sexy black thong that clings to her pussy, which is wet enough to have dampened her underwear. She then slides the thong down her legs and unclips her bra. "Now fold your clothes," Stacey orders. "Once you're done, ask with your head bowed." Olivia nods mutely, dropping to her knees. She folds up your clothes and makes a neat pile of them before Stacey, who looks down from atop her mattress. Then Olivia lowers her face into the carpet. "Please, Stacey, Finn, make me your toy for tonight." She breaths, shuddering. You take a good long look at her heart-shaped ass then glanced up at Stacey. Stacey makes a writing gesture. "I am going to cast a spell on you, in that case," Stacey says. "Finn, make the preparations."

You nod, removing the marker from your pocket. You walk over to Olivia and gesture for her to lift her body up, so you can write on her back. You write, "Cannot see Marker's writing" and "All changes will happen when Stacey or I snap our fingers." Then you begin writing furiously. You quickly write "Elastic Holes", "No pain when penetrated", "Orgasms when someone cums inside her" and finally, "Can breathe through skin if airway is obstructed". Then you stand and conceal the marker. "The runes are in place." Stacey then says something in a language Olivia wouldn't know. You didn't either, she had made it up. Then she snaps her fingers. Olivia blinks. "Huh? Nothing happened." Stacey smiled. "Trust me, you've changed. Here, let me prove it to you." She gestured to you. "Finn, let Olivia suck your dick."

You were worried there for a second, none of those changes were visible. But Stacey had it all under control the whole time. You should have never doubted her. Still, you had one kernel of doubt left. Stacey had written all your changes on your back and then set a condition for their implementation. All you could do was trust that she had written the right stuff. You kick off your shoes and peel off your shirt, then start on your shorts. "Wait," Stacey says. She turns to Olivia. "Suck on his index finger. Right hand." That's the trigger, you remember. Olivia, still naked and kneeling, turns on the ground to face you. You extend your hand toward her, offering it. She takes it and sticks your index finger into her mouth, sucking softly on it. Immediately, you feel the marker's power change you. Your underwear tightens and you feel a sudden pressure in your erect cock. You smile, but keep your mouth shut, and pull down your shorts. Tossing them aside, you stand there in your boxer briefs, lifting your hands and gesturing to them. Olivia nods, gulping a bit at your bulge.

Then, grabbing your waistband, she tugs them down. Immediately, your cock is freed and swings forward, smacking her in the face. She squeaks, stunned at the sight of your cock. It is much bigger than normal, not superhumanly so, but elephantine, huge and low with a purple-hued head; a thick, throbbing shaft and balls the size of apricots. "12 Inch Cock" had been your request. You smile at her, but don't say anything. She gulps at the devilish grin on your face, then looks up at Olivia. Olivia leans back and begins rubbing the top of her panties. "Don't stop, please. Keep going." You poke Olivia in the face with your hard cock, pre leaking from the slit and dabbbing her face. She nods in Stacey's direction, then begins to lick. Grasping the base of the shaft, she laps up your pre and begins to lavish the head with the wonderful warmth of her tongue. It feels good, but it's not enough. You thrust into her mouth, poking her cheek and stretching it out. Olivia pulls your cock out of her mouth. "I'm sorry, Finn, I can't take something that big." In response, you grab her head firmly and gently push her forward. "Don't worry," Stacey mutters, her voice thick with arousal. "His magic will protect you. Just give it your best shot."

Olivia nods, then tries again. This time she swallows as much of the shaft as she can. She begins to slow about halfway through, reaching her natural limit. You tremble a bit at the wonderful sensations of her tight, wet mouth. You need more. You thrust into her mouth and Olivia gags for a second, before pausing. She stops sucking and stares up at you in amazement. Your cock is 3/4 in her mouth ahd down her throat, but she can still breathe. Even better, her mouth seems like it has more room, as you can feel. As she realizes this, a glint appears in her eyes. She takes in more of your cock, slurping it all the way down the base. Then she begins to suck vigorously, moving her mouth up and down. You spasm, grabbing onto her head for support. It's like a throatfuck, but she's the one doing the fucking. Her mouth rides up and down on you, the pressure and warmth never ceasing. Saliva pours out of the tight ring of her lips, mixing with your pre and coating your entire cock, making it slide in and out even faster. Olivia then shoves you in as deep as you can go, your balls mashing into her chin, her hands reaching around to grab your ass and shove your cock in as far as it goes. It's heavenly. Your balls tighten up against your shaft and pressure that had been building since she sucked on your finger expands. Your balls are on the verge of popping, your cock is tensing in anticipation. Then Olivia opens her mouth even wider, the marker boosting the elasticity of her mouth-hole so it can swing open like a snake. Extending her long, slurping tongue, she sucks your balls into her mouth. The sensation is enough. You tremble like a building in an earthquake as your cock finally surrenders and erupts.

Cum gushes into Olivia's throat, filling her mouth to the brim. Cum sprays out of her nose as she struggles to swallow, while you grab her face to keep your cock clamped inside. As you cum, a massive orgasm explodes up inside her, making her mouth go limp, allowing you to thrust in even deeper to pour cum straight down her throat. After a second of feeling her gasp, you yank your cock out and spray what's left of it across her face and large, perky tits. Olivia nearly falls over, barely catching herself on all fours. You stumble a bit as well, before grabbing hold of the edge of the bed. Stacey did write, "Enormous Amounts of Cum" you idly think. And judging by the way your cock had only shrunk to half-hardness, you had a feeling an inspection would also find, "Rapid Recovery" as well.

Stacey pats you on the shoulder, then glances down at Olivia. She's nearly lying on the carpet at the foot of the bed, her face and tits sprayed with pearly white strands, her face flushed. Stacey smiles pleasingly at this display, then extends a hand. You kiss it, like a knight taking the hand of a gentlewoman. "That was a lovely warm-up," Stacey commented dryly as the marker's power started to change her as well. "Now, let's get started."