Of course not, you keep fucking your Sister into the early hours of the morning

Once that proverbial cork was popped, there wasn't any putting it back in the bottle, not when you could look down and see the first serving oozing out of Ruby's pussy and leaking down onto your body. Even now having only finished a few minutes ago, your cock is already starting to swell back to life, blood rushing back down to your shaft, just from having your Older Sister's naked form resting on top of you. Your eyes flick over to Ruby's face, her own eyes catching yours and a mischievous smirk spreading across her face as you both come to the unspoken understanding that neither of you is close to being done.

Ruby is the first to move, sliding herself across your body, one hand reaching over and cupping your face as she moves in, pressing her soft lips to yours, her tongue extending out and exploring your mouth. You eagerly return your Older Sister's kiss, moving your hands up to finally have free reign to cup, fondle and play with your Big Sister's big tits. Ruby's sweet moaning into your mouth, while you tease and squeeze her boobs, spurring you on. Soon your cock is once again rock hard and raring to go.

You continue to kiss and fondle your Older Sister until you can't wait any longer, rolling Ruby onto her back and spreading her legs wide. Grasping one of your Sister's ankles in each hand you use your hips to guide your swollen shaft forward, teasing yourself against your Sister's slit. Each time your bulbous tip connects with Ruby's slippery sex, you hear her let out a gasp of pleasure, the anticipation and need to feel you inside of her growing with each prod. You deliberately keep yourself from gently thrusting at the right angle to penetrate, your cock slipping out of your Sister each time you get close to slipping inside. You can hear Ruby's nails clawing into the sheets with the frustration of your teasing.

"Not so fun, being on the other side is it?" You reply with a confident tone.

"Screw you," Ruby replies with a hiss as your cock once more pops free from between your Sister's lower lips, your shaft sliding against her swollen clit.

"You already have," You joke back.

"Encore," Ruby replies.

You smile and let out a soft laugh, unable to argue with your Sister's reply and also not really wanting to tease her for much longer given how horny you are, you adjust your hips slightly and thrust forward, sinking every inch of your thick cock into your Sister's sweet sex. Lubricated by a mixture of your own and your sister's previous orgasm mean you don't have to wait long before you pick up the tempo and start pounding Ruby. Your balls slapping into her, so far untouched ass with each rough thrust. Ruby squealing and crying out in pleasure as you rail her.

At some point in your savage thrusting your own hands moved down to grip your Big Sister by her hips, her legs resting against your body, her ankles by your ears as you thrust down into her. You watch with a sense of delight seeing your Older Sister's face contorting with pleasure, her guttural moans of pleasure as your body slams into her. Ruby's hands, now resting on your outstretched arms, dig into your soft skin, almost drawing blood as she starts to spasm beneath you as you roughly fuck her through her orgasm. The soft wet walls of her sex caress and squeeze your shaft as it continues to thunder through them.

After about the third time of making Ruby cum on your cock in this position and pace, you decide to ease up on her a little, the night was relatively young after all and you didn't want to wear your, Big Sis, out so soon. You also needed to slow your own pace, given you could feel that familiar tingling in your balls as they begin to start getting to work ensuring you have a nice thick load ready to go.

"Mmmm fuck, I didn't think you had it in you, Sis," Ruby pants.

"Well, the line was crossed, seemed a waste not to show you what I can do," You reply with a giggle.

Ruby starts to giggle along with you, sliding her hands up your arms until she can reach your neck, where she pulls you down for a kiss. The movement also forces you back inside of your Sister's still twitching folds, the glorious aftershock of her more recent orgasm, gently massages your shaft, doing little to help you arrest the start of your own orgasm. Still, you enjoy the feeling of feeling Ruby's hot sweaty body pressing against your own, her pussy gently squeezing your thick length, while your tongues mingle and dance together. It's a strangely peaceful moment, given the earlier frantic and chaotic coupling. This is just what your Big Sister was banking on, as you let yourself get caught up in the moment.

In an explosion of movement, you feel Ruby's form wriggle just for a moment, before suddenly her legs hook around your back, and lock you in place. The sudden movement catches you by surprise, not the least because, in all of this, your Older Sister is still kissing you. You open your eyes and see Ruby looking back at you with a familiar glimmer of mischief in them.

"What's with the leg lock?" You ask, breaking the kiss.

"Just making sure, you're not going anywhere," Ruby replies in an evasive tone.

"Hard to imagine anywhere else I'd rather be right now," You reply in a smooth tone, slowly rolling your hips to grind your cock deep inside your Older Sister, for emphasis.

Ruby goes along with your grinding for a few moments, enjoying the feeling of you being balls deep inside of her until she begins to buck her hips against you, causing you to slide the last inch of your cock in and out of her. The feeling is exquisite, fresh waves of pleasure quickly flood your still slightly lust-addled brain as almost every inch of your cock is brushing against the hot wet silk-like walls of your Big Sister's sex. The sensation quickly stocking that fire, from the tiny ember you felt earlier into a steady and growing heat and pressure.

"Mmmm, flattery will get you everywhere, Dear Sister," Ruby replies between long moans of bliss. "But you might not be so sure, when I tell you my little secret," Ruby purrs, tightening the grip her legs have on you, ensuring outside of something drastic, you wouldn't be getting free of her grip.

"Secrets, I think we're a little bit beyond that," You reply with a grimace of pleasure as Ruby starts using her kegel muscles to massage your cock, which coupled with the thrusting was quickly getting you close.

"I know, but it's a little embarrassing, so can I whisper it?" Ruby asks with a smile.

You're not quite sure what Ruby's up to at this point, however, you've been enjoying yourself so far, not having to worry about any lasting consequences of the night for a change. Not that the worry of impregnating either your, Aunt, Cousin or Half-Sister really stopped you before, but you didn't quite feel as in control back then as you did now.

"So I might not have been entirely truthful earlier?" Ruby whispers between low sensual moans, her hot breath sending a shiver down your spine.

"You knew the tests would end like this all along?" You whisper back, feeling your cock begin to swell and your balls churning as you feel that point of no return swiftly approaching.

"That too," Ruby whispers back with a flirt giggle, her hands moving up and around your body, softly stroking your back.

"Figures, although not that I'm complaining, a perfect way to end the night," You reply in a soft tone, feeling your swollen cock twitch heavily.

"Indeed," Ruby agrees, her words fading into a long purr of pleasure before she lightly bites your neck and sucks on the skin, giving you another hickey to match the one from earlier on the other side of your neck, both too high up for you to easily hide with clothing. "So earlier, when I told you it was the wrong point in my cycle to get pregnant," Ruby asks in a slow sensual whisper, elongating each and every word to give her as much time to get you closer and closer to the edge.

"Yeah," You whisper back in a hoarse tone, your cock now fully swollen and leaking precum, while Ruby's sweet pussy does everything it can to make you try and cum.

"Well I wasn't entirely truthful," Ruby whispers back, locking eyes with yours a wicked smile on her lips.

"What?" You reply in a grunt, feeling your cock give two warning twitches in quick succession as you feel yourself quickly losing your grip while you feel a sense of apprehension about what your Big Sister was about to tell you.

"Well, what I really should have said is that there are better days you could cum in me to knock me up," Ruby replies with a grin. "Like in a few days," Ruby continues before pulling herself next to your ear. "Or maybe even less, I haven't been keeping the best track of when I ovulate recently," Ruby whispers into your ear.

"Gotta pull out," You groan, feeling your balls rising as your cum begins to flow up towards your shaft.

You were barely holding on before, and while you do make one effort to try and slip free of Ruby's leg lock, managing to get a few inches out. You quickly realise this is only because your Older Sister wants you to do so, in order to pull your back into her in one quick thrust and tip you over the edge as she whispers. "Who knows, maybe I'm ovulating right now, It would explain why I've been so horny," Ruby whispers. "Now cum for me Little Sister, feel me with that hot thick cum," She pants, reaching her hands out and gripping your ass with both hands, her fingernails digging into them and she tries to pull you even deeper into her.

Unable to resist, you resign yourself to once again fill another family member with your thick potent cum. Listening to Ruby whisper and moan into your ear as your cock throbs and pulses, sending wave after wave of your seed into your Older Sister's unprotected and potentially incredibly fertile womb. You could be annoyed, angry even, at your Older Siblings' possible betrayal, but it's hard to get mad when everything feels as good as it does. Besides, you'd already filled Ruby with a heavy load earlier, what's a few more hundred million of your healthy swimmers when her womb would already be swarming with them, eagerly trying to seek out an egg to fertilise.

What you do decide to do once you finish blasting a fresh batch of baby makers into Ruby, is spend the rest of the night, fucking her in every which way you can imagine. You fuck long into the night until neither of you can continue, and the sun begins to rise in the early hours of the morning, the pair of you lying atop a thoroughly messy and stained bed, falling asleep cuddling against one another.