Limestone didn't notice that her sister was admiring her until Marble's hands reached out and gripped onto her waist before running her hands up and down, caressing Limestone's skin through the silky fabric of her pajamas. Limestone went "Marble... what... what are y-you doing?" Marble, as expected, didn't say a word, instead she did the rather unexpected as she leaned forward with her eyes closes and pressed her lips against Limestone's in a sensual kiss. Limestone released her grip on Marble's shoulders in shock, which Marble took advantage of by moving closer and wrapping her arms around her sister, raking her fingers through her hair as she deepened the kiss while moaning gently in the back of her throat. Limestone's eyes were wide open and her whole body was tensed, of all the things she imagined could have happened in this situation a kiss was not one of them, certainly not one that felt so...... romantic. As the kiss continued, Limestone slowly began to relax, her whole body felt warm and tingly, particularly in between her legs as her pussy began to moisten, eventually however. Marble pulled back and broke the kiss and simply stood there with a blush on her face.

Everything went silent, both of their heavy breathing barely audible as they both came to terms with what had just transpired, they were both speechless. As Limestone and Marble looked into each other's eyes, they sensed an unspoken message, for once they had a mutual understanding, they communicated and connected with each other for the first time without having to say a single word, one look into each other's eyes was all it took to bridge the metaphorical gap between them. That's when Limestone decided to bridge the physical gap between them by moving forward and resuming the kiss, only this time much more passionately, much more enthusiastically, much more...... lustfully. Limestone was briefly surprised that Marble reciprocated so eagerly as their tongues wrestled inside each other's mouths, both of them using their hands to roam around and explore each other's bodies as their pussies only got more and more damp by the second. Limestone was the one to take it a step further and made Marble gasp with excitement and anticipation when she started sliding a hand down the front of her pajama bottoms towards her sensitive cunt, the kiss continued while Limestone began rubbing Marble's pussy with the intent to bring her to a strong orgasm as quick as possible and was relentless in her assault on every single available part of her sisters most private areas to ensure that she got what she wanted.

Marble let out a small squeak as Limestone, almost expertly, slid two fingers inside her sisters sopping wet cunny and began pumping them in and out, making sure that each time she got her fingers to rub up against Marble's g-spot that she used her thumb to press and play with her clit at the same time to heighten the pleasure. Marble and Limestone were struggling to concentrate on kissing and enjoying some pussy play at the same time, both due to lack of focus through the haze of lust and also just sheer lack of energy, though they refused to stop, Marble wasn't really in a position to take a break and Limestone wasn't going to stop until she got Marble to ruin her own pajama bottoms by soaking them with her female fuck fluids. Their perseverance paid off as seconds later, Marble squealed into Limestone's mouth as her slippery pussy clamped and clenched down on her fingers, drenching her sisters hand as well as her own pajama bottoms as juices gushed from her heavily stimulated fuck hole, now it was Limestone's turn to cum. They began to move towards Marbles bed until Limestone fell back onto it with Marble landing on top of her, where upon they finally broke the kiss in order to catch their breath and hopefully move on to something even more intimately sexual with each other, which came not even two minutes later as Limestone started pushing down on Marbles head in order to coerce into moving down the bed so that she could get herself tended to, she wanted Marble to eat her pussy.

Marble got the message the second she felt Limestone place a hand on her head and started moving down the bed, already licking her lips as she prepared to get her mouth around her sisters hot aching cunt. Marble pulled down Limestone's pajama bottoms and her nostrils were immediately greeted by the scent of pure female arousal, a smell that made Marble shudder and salivate as she laid eyes on Limestone's entrance, shining in the dim light of her bedroom, Marble had never been more turned out or more hungry in her life then she was right then and there with her head in between her sisters legs, her face mere inches away from a pussy that was begging and pleading to be touched, pulsing with need. Marble placed a delicate kiss on each thigh before burying her face into Limestone's most sacred yet desperate space and began licking with every ounce of might in her body, the taste that coated her tongue was a unique yet addictive flavor that Marble couldn't get enough of and she was going to get as much of it as she could until Limestone orgasmed, which she hoped would result herself getting a generous mouthful of the delicious substance right from the source.

Limestone grit her teeth and grunted as she held onto Marbles head, she hadn't expected her to be so energetic, it was very out of character for her but Limestone wasn't exactly complaining. Marble just devoured as much pussy as she could, her taste buds couldn't get enough of Limestone's taste, her tongue thrashing wildly and without precision as she lavished the quivering pink folds with affection, though judging from her sisters reactions she figured that searching for the g-spot or stimulating the clit may not have been entirely necessary, it seemed she liked it messy. The slow build up of pleasure and frustration continued to grow in Limestone's groin, she felt like her crotch was about to burst and in a certain kind of sense, it did, as Limestone groaned loudly and Marble got her wish of receiving a plentiful amount of girl cum that she swallowed gleefully, it seemed they were both highly sensitive that evening and they had both orgasmed far sooner than they thought they would. Limestone let go of Marbles head, allowing Marble to remove herself and climb back up the bed to lie next to her sister as they both fell into a deep slumber from the exhaustion of having just experienced some incestuous lesbian sex together.

The following morning, sunshine spilled into the room and forced Limestone and Marble to wake up with a yawn. Limestone grumbled and went "Ugh... if having sex with your siblings is so tiring I'm not even sure I want it to be legal, same goes for bestiality, though that's not something I ever intend to try anyway. Morning Marble"

Limestone got the shock of her life as a voice that she had never heard before replied to her, Marble, almost without thinking said "Good Morning Limestone".

Limestone froze as she turned to look at Marble before saying "You... you talked... you don't talk, you never talk... why are you talking? You're talking!"

Marble looked at Limestone as if she didn't know what she was talking about before she seemingly caught what she had done and confidently said "Oh yes, that's right... I'm talking, I'm talking Limestone! I'm talking!"

Once again, Limestone reacted completely opposite to how Marble had expected her to react as she said "Shut up! Stop it! Stop talking!" Limestone got out of the bed and turned away from Marble with a scowl on her face, she didn't show it but she was deeply saddened by this turn of events, not because of the sex itself but because of what the sex might mean. This time however, Marble was the one who was genuinely pissed off, her sister was sending her so many mixed signals and now that she was finally talking, she was going to use her voice.

Marble got up, grabbed onto Limestone's shoulders, turned her around and staring deep into her eyes said "Four words bitch, shut... the... fuck... up... do you want me to talk or not? Quite frankly I'm sick and tired of your bullshit, so let me give you a taste of your own medicine, talk to me. I'll stand here and listen while you talk, don't close up, don't run away, don't ignore this, connect and communicate with me, talk"

There was a small silence, Limestone pleading with Marble through facial expression alone, begging her not force her to talk about her emotions. Marble didn't waver, Limestone let out a sigh and launched into an honest speech about how she was feeling. "Look Marble I just... I feel conflicted about this OK? Believe me the sex was great and I wouldn't take it back but... the whole thing with you talking I just... I don't know how I feel about it. When Pinkie and Maud left, the only sister I had was you and talking to you was difficult because you didn't talk back, I wanted a sisterly bond with you and I felt like I couldn't achieve it and that maybe on some level you didn't even want it because you refused to speak. After that I just wanted to know why... why you didn't speak, why you didn't care enough about me to force yourself to attempt a conversation, that's when we had sex and now you're talking I just... well now you do care, I'm not saying I don't want you to care but since we're slightly more than sisters now I just... if you leave the rock farm or whatever to do your own thing it'll just break me... now that you care... you're just one more thing for me to lose......"

Marble was on the verge of tears as she brought Limestone in for a hug "I won't leave you Limestone, I promise... well, on one condition..."

Limestone said "What condition?"

Marble smirked as she broke the hug, looked at her sister and said "Can we from now on and forever not get all sappy and emotional about this shit? I mean it's not like we're going out, we can just be fuck buddies, deal?"

Limestone chuckled, back to her old self again and said "Sure, deal. We should probably chuck our pajamas in the wash though, call me a prude but I don't exactly want both of our bedroom stuff reeking of pussy the whole time". They both went out into the hallway, taking off their pajamas and throwing them haphazardly into the kitchen vaguely near where the washing machine was, standing there in the nude Limestone went "By the way, I want to establish a dynamic here, I'm totally cool with us fucking as much as possible but there is gonna be rules, so you got any questions ask them now"

Out of the blue, though Marble appreciated that Limestone was cutting to the chase "OK... um... strap-ons?"

Limestone said "I'm the dominant one in this relationship and you're the submissive one, if we use strap-ons I'm gonna be the only one to wear it so that I can fuck you, anything else?"

Marble nervously went "Um... b-bestiality?"

Limestone just flat out in as monotone a voice as possible said "No"

Marble thought of other things she could ask but they were all minor things they could work out later, she nodded to signal that her curiosity was satisfied. Limestone smiled and said "Good, now with that out of the way...", Limestone walked up to Marble and pressed their chests together as she continued "Now I say we fuck again right now, we only focused on pussy last night and I really wanna play around with your fucking tits..."

Marble grinned as she wrapped her arms around Limestone's waist and grabbed a good handful of her butt cheeks and said "So long as I get to have some fun with your ass, then I'm game". As they began to kiss their eyes went wide as they heard clicking at the front door, it seemed their parents had returned early from their trip. they couldn't imagine their parents being happy about this, so as quick as a flash they separated and went to their respective bedrooms to do some pretend sleeping, the sex could wait for another day.

-present day-

Still after all these years, their parents had no idea. True to their word, they formed a fairly solid relationship after that, they talked, they worked together, they fucked each other every chance they got, life was good.

The End

Author's Note

Thank you UndeadMan for this story idea! I hope you enjoyed it :)