You get swept up in the moment and suggest a different type of Gambling

It's a long drive to Vegas from where you and your sister are staying, especially when with each slight bump and uneven surface of the road you can feel more of your Sister's cum leaking out of your pussy. Still, you ensure that Lyra gets a similar experience with your hand resting on her thigh and occasionally drifting over her crotch, where you slowly tease her slumbering beast to full hardness before sliding your hand away. By the time you reach the city of sin, neither of you is in the mood to stop in and take the sights, instead, you both go straight up to your room.

The moment the elevator doors close Lyra turns on you pressing you against the wall with her stronger futa frame, her lips pressing against yours in an aggressive but passionate display to the other guests that get on and off. For a moment you thought Your Sister might not wait until you reach your room before having her way with you with how eagerly and unashamedly her hands explore your body over your clothes. Fortunately, you arrive on your floor and Lyra practically drags you down the hallway, stopping at a doorway to kiss you once more while Lyra fumbles with the keycard.

The door suddenly swings open the pair of you tumbling across the threshold and landing on the floor, your Sister on top of you with a hunger in her eyes, unlike anything you've seen before. She leans down and presses her soft lips against yours, kissing you with passion and a hint of aggression, you can feel cock rock hard cock pressing into your body even through all those layers of clothes. If it weren't already obvious by now you'd suspect you might have gone a little too far teasing your younger Sister all the way here.

You feel Lyra's hands start to roam over your body, caressing and cupping your boobs while she continues to make out with you on the floor of the hotel room, the door still wide open for all passersby to see. You are pretty sure that eventually your Sister will move things to the bed and shut the door to your room, but when Lyra starts to undress you, you realise you'll need to be the one to prompt that move or be content with having hot incestuous sex with a possible audience.

"Don't want to stop you, but we should really get some privacy," You manage to say between kisses.

For a moment you're not sure if Lyra is listening as she continues to lift your top revealing your tits for all to see, her lips breaking away from your mouth to wrap around one of your nipples. You let out a loud hiss of pleasure as Lyra sucks and nibbles on your swollen nub, you hear a cheer from the hallway as some people walking past see you with your Sister on top of you. Lyra lifts herself up with a big smile on her face as she turns to face the spectators, a small group of young women in skimpy dresses with sashes on saying bridal party.

"Shit, some girls have all the luck," One of them says as she notices the huge prominent bulge of Lyra's rock-hard cock straining against her clothes.

"I hope you enjoyed the show, now if you'll excuse me I have a bed to break with my Sis," Lyra replies giving the women a polite bow before closing the doors.

"Wait what did she mean by Sis?" You hear faintly muffled through the door.

Finally with some privacy and a small group of women off to hit up the casinos and spend the night wondering about the kinky couple who they think were roleplaying **** or not, things can progress. Lyra leans down helps you up to your feet and begins to walk you back towards the large bed, undressing and kissing you on the way, leaving a trail of clothing from the door to the bed.

You go to kneel down and take your Sister's cock in your mouth, but her strong on your shoulders stops you in your tracks. "As much as I'd love that, I need to be inside you," Lyra says in a sensual yet commanding tone.

"Was the teasing too much?" You reply with a soft giggle.

"Let's just say it's got me so worked up, that I'm going to pump you so full of my cum, that it'll be a miracle if the morning-after pill even works," Lyra replies in a smooth tone.

The words make you shiver with an illicit thrill, the knowledge that your Sister will be sliding her big fat Futa cock deep inside of you with no protection, then painting the pink walls of your defenceless womb white with her potent futa seed. Sure this is all just fantasy talk, but damn if it wasn't having a profound effect on you. The thought of getting knocked up by your younger Sister sends a mixture of fear and excitement coursing through your whole body, that part of you that wanted to start a family especially resonating with the fantasy.

You smile back at Lyra deciding to play into her fantasy. "Promises, Promises," You reply.

You notice a look of surprise on Lyra's face for a moment before it quickly changes into an evil smile as she picks you up and throws you back onto the bed, quickly climbing on after you and sliding between your legs. The tip of her swollen cock, sticky with precum slides between the folds of your soaking slit, and then with barely a moment's hesitation Lyra thrusts forward. You feel the walls of your slick sex part around your Sister's thick mass, without a condom the sensation is overwhelming. The dizzying rush of raw skin-to-skin contact with your Sister's cock makes your body quake and your toes curl as she sinks effortlessly inside you.

"How does your Sister's cock feel without a condom?" Lyra asks with a grunt of pleasure.

"So good," You groan back through a surprise orgasm that hits just as Lyra bottoms out inside of you. "So wrong, but so good," You add while your entire body shakes.

"Can you feel my balls against your ass?" Lyra asks in a teasing tone, flexing her cock inside of you for emphasis. "Can you feel how heavy they are, Sis?" Lyra asks.

"Yes," You whimper back

"Your teasing made them that full and heavy," Lyra says in a sensual tone. "Got them overflowing with incestuous cum," She adds in a sensual growl.

"Oh god," You groan, a fresh wave of pleasure hitting you as Lyra begins to grind herself in a circular motion while still deep inside of you.

"Now I need to empty them," Lyra continues, "So to pay you back for all that teasing, I'm going to empty them right where I am," She concludes with a growl.

"Please, Sis, I could get pregnant," You plead back, as you play along with what you believe is roleplay.

"I know you could," Lyra replies, moving a hand over your flat stomach. "But you were teasing me the whole drive over, for hours and hours," Lyra says in a soft tone. "So now to punish you, I'm going to fucking breed you," Lyra growls, finally sliding her cock out before thrusting the full length of her cock back inside you.

"Please, Sis," You plead between moans. "I can't get pregnant," You add.

"Oh, I'm certain you can and will," Lyra growls as her thrusting grows more intense. Each time your Sister's cock bottoms out in you, the tip of her cock presses heavily into your cervix, a shart shock of pain which is lost in the sea of pleasure.

"What will Mom say, when she finds out," You continue to plead between moans and groans of pleasure, your own mind lost in the dizzying illicit thrill of imagining a taboo pregnancy, the scandal of it all.

"I'm sure she'll be thrilled to hear she's finally getting grandkids," Lyra groans. "Might be less pleased when she finds out who knocked you up," She adds with a laugh. "But once she sees you all big and swollen with my baby, tits all swollen with milk, she'll forget all bout that," Lyra adds with a grunt, her cock twitching inside of you, spraying your cervix with a fresh batch of precum.

"Please don't breed me," You plead ineffectually, the mental images painted by your Sister's words still swirling around your mind and triggering another shockwave of illicit thrill, while your legs hook around Lyra's back.

"I think your mind is saying one thing, but your body is saying quite the opposite Mist," Lyra replies with a broad smile. "Would it really be that bad, having me knock you up?" Lyra asks with a grunt, her already rock-hard cock starting the swell and twitch more uncontrollably as her balls begin to churn and writhe with activity as your Sister begins to approach her limit.

"Please," You beg between loud throaty moans of pleasure.

"Mom will forgive us," Lyra says with a giggle, "Hell maybe she might be jealous and want me to knock her up too, what do you think, Sis?" Lyra adds with a sensual laugh as she continues to pound your pussy.

"So fucking wrong," You groan while hooking your legs together, effectively keeping your Sister from being able to pull out, not that she has any intention of doing so.

"Yeah, so wrong that it's right," Lyra growls her thrusting picking up the pace even more as her rock-hard cock gives a warning throb inside of you. "Maybe we'll even get Ms Genevieve involved in our twisted little family," Lyra adds with a groan of pleasure, "I'm sure she's hooking up with Mom," Lyra adds with a giggle. "Came back early from staying at a friend's house, to hear Mom moaning 'Don't stop Genie'," Lyra pants, rapidly approaching that point of no return.

"Oh god," You groan in reply, your mind now swimming with the thought of you standing beside your Mom and the woman who helped raise you, bellies all swollen with Lyra's kids. "So wrong..." You begin before your words fade into a hiss of raw pleasure.

"But so right," Lyra concludes with a laugh. "Now beg for it," She demands in a sensual growl.

"Beg for it?" You reply your entire body ablaze with pleasure at the sensory overload.

"Beg for my cum, beg for me to knock you up," Lyra growls, her thrusts now uneven and animalist.

"Oh fuck," You groan, "Do it," You add, feeling your Sister's heavy balls drag upwards as they begin to pump thick potent cargo towards Lyra's swollen cock.

"Do what?" Lyra replies in a teasing tone.

"Cum in me," You groan. "Fucking breed your big Sister," You scream, unsure and uncaring if the walls were soundproof enough to hide the taboo nature of this fucking.

"Oh fuck yes," Lyra growls. "Fuck going to cum so hard," She adds, giving you one final and heavy thrust, the tip of her throbbing cock embedding itself into your cervix, giving her direct access to your womb.

The realisation of what you're about to do starts to hit home at this moment, it was one thing to have Lyra accidentally fill you with her cum, but quite another to be willing to welcome it and even beg for it. Through all the haze of the orgasms, you hadn't really been aware of what you were giving up at that moment. The moment you feel your Sister's thick futa fuckstick begin to throb and pulse deep inside of you, followed shortly by a sweet sticky heat spreading deep in your womb, you realise there's no going back.

There's one thing you can be certain of while your start to climax alongside your Sister, holding her tightly while her cock pumps rope after rope of her thick potent futa seed. While Lyra would probably go back to using condoms if you insisted enough, you couldn't imagine ever wanting to give up this feeling. The warm rush of your Sister's cum flooding your most intimate place, the dizzying difference between using condoms and bareback sex and that pure intoxicating rush coursing through you as you cum, knowing that at this moment there's nothing to stop your Sister's seed from taking root and committing the ultimate taboo.

Even now as you lie back still clinging to your younger Sister as she pumps the last of her cum deep inside of you, there are parts of your brain trying to rationalise letting nature take its course. You push the thoughts away, fantasy is one thing, but reality is a much messier beast, yet despite this, the thoughts come creeping back. Even as you drift off to sleep as exhaustion claims you and your Sister, your dreams are filled with scenes of you carrying Lyra's child.

The next morning you wake up and after a hot shower, you make your way to the nearest pharmacy while Lyra stays behind to set up some equipment for recording and unbeknownst to you speaks to her contact at the hotel about the hidden footage of last night. You're able to pick up the morning-after pill from the nearby pharmacy by the looks of it a few women are doing the same including one you recognise from the women who watched your Sister grope you. She doesn't say anything but gives you a smile and wave, which you return, although seeing her this close you spot a badge saying bride to be.

On your walk back to the hotel you glance down at the innocuous box stashed in your handbag and consider the contents and all it means within with all the events of the previous night running through your mind. As you pass the lobby the discord of various video poker machines and other sounds of gambling catch your attention. You never saw the appeal of gambling, knowing how poor the odds were, but as you watch people pour dollar after dollar in the hopes of catching that elusive big win, something clicks within you. Perhaps you just hadn't considered playing for the right stakes. On the ride up the elevator, your mind begins to turn and you come up with something you hope would scratch the itch you discovered last night while adding some extra fun to the trip.

"How did it go?" Lyra asks giving you a big smile as she looks up from her laptop.

"No hassle or judgement, I even saw one of the women who were cheering us on last night picking some up," You reply with a soft laugh, taking out the box and placing it on the table.

"Oh shit, I guess we inspired them with our show," Lyra replies with a giggle.

"The bride-to-be, no less," You say with a soft laugh.

"Well, it is Vegas, people joke about the saying, but it exists for a reason," Lyra replies with a grin.

"True, which reminds me, we're here a day and night before heading back, do we have anything planned?" You ask with a grin. "Besides the obvious fun we'll be having together," You add with a giggle.

"Not sure, do some touristy crap, take in a show and get good food, we could spend a bit of time in the casino if you want," Lyra replies with a smile. "Although I feel like casino time is time we could just spend having our own fun," She adds with a sensual look.

"Yeah I know what you mean, I know coming to Vegas and not gambling even a little is almost a crime to some people, but If I had to pick between sitting downstairs maybe winning money, or riding that magical cock of yours, no contest on which I'm picking," You reply with a grin.

"I think I might have made a monster," Lyra replies with a giggle.

"A very sexy monster," You reply with a giggle. "And a smart one too, since I think I've come up with a solution to the gambling thing that you'll love," You add with a wry smile.

"Oooooh, do tell Sister dearest," Lyra replies closing the laptop and giving you her undivided attention.

"So we have one morning-after pill, which If I take now means we have to either use condoms or trust you to pull out," You explain with a smile. "The smart and safe, but boring option," You add with a smile.

"Oh I think I like where this is going," Lyra replies with an excited grin.

"Or I could take it later, give your swimmers a little time to swim and play in my gene pool, a small risk but should be safe, and enjoy feeling you fuck me raw and filling me with your cum again and again," You purr feeling yourself getting wet at the idea.

"Oh fuck, I love that idea," Lyra says excitedly, glancing over and hoping the hidden cameras were still recording and capturing this gold, even if only the audio will be used in the edit for the project fruits stuff for the taboo fan site.

"Then the biggest risk, I don't take it until we get back to the lodge and give your futa seed 2 whole days to do what they can to my poor defenceless body," You reply with a big grin. "I'll just be in the last few hours of efficacy for when the condom broke, so it's a much bigger risk but should still be safe," You continue with a grin. "But all that time you'll be able to think about what if your sperm is fertilising me, what if it's too late by the time I take the pill," You conclude with a smile.

"Fuck that's so hot," Lyra replies.

"But to get that, you'll have to play for it, which makes it a gamble," You explain with a smile. "Don't worry it's a game you know and love," You add with a soft laugh.

"What do I have to do?" Lyra asks excitedly.

"All you have to do is fuck me and make me cum as many times as you can before cumming," You explain with a smile. "If you can't make me cum more than 3 times before you pop then I take the pill once we're done and we have to use condoms or pull out the rest of the trip. "If you can manage more than 6 I'll take it at the end of the trip, If you can make me cum more than 9 times then I'll take it when we get back to the lodge," You continue with a grin. "Rules are simple, orgasms only count while we're fucking, you're only allowed to take your cock out of me to change positions and finally you have to cum inside me," You conclude with a grin. "So, any questions?" You ask.

"What will we do if I do get you pregnant?" Lyra asks with a broad smile.

"We'll cross that bridge if and when we come to it, Sis," You reply with a big smile. "So do you accept my little biological bet?" You ask with a soft laugh

"You bet your ass I do, Mist," Lyra replies with a grin, her cock already throbbing in anticipation about possibly breeding you.

"Perfect, now I think we should enjoy the day relaxing and save the game for this evening," You say with an evil smile, knowing just how frustrated Lyra's going to be trying to do a full day of going around Vegas while her mind is on your body.