Reluctantly accept...

You bite your lower lip, knowing you might regret this later but... "F-fine." You say, turning away from the minx on top of you. Her face shines with delight as she quickly reaches down, grabbing your cock. She coos softly as she rubs the tip of it against her entrance, letting her juices slowly trickle along it's length, before she begins to press her weight downwards and for the second time that night, you feel your dick enveloped in walls of warm pulsing flesh. Her eyes roll into the back of her head as she places her hands on your stomach and moans. You both stay their for a second, panting, before Shelly begins to bounce up and down, her movements more sporadic than Bella's, but nonetheless heavenly to experience. You let her take the lead for a while, happy to just enjoy the sex, but slowly the pleasure takes hold of your mind, as you grab her by the hips and begin to thrust with your sister. She looks down at you, making eye contact as she let's out a series of lewd noises and she lays down on you slowly, not stopping her movements for even a moments, before bringing her face close to yours, her luscious red lips moving closer to yours, before colliding with them, your mind too clouded to think about the fact this is your sister, you kiss back passionately, enjoying the sweet, yet salty taste of her lips on yours, as her movements speed up and she moans into your mouth before...

"JOHN?" You hear your Mom yell from downstairs. You reluctantly break off the kiss as your sister, pouting slightly, adjusts and begins to kiss your neck.

"Y-yeah ma?" You call back.

"I'M GOING OUT TO THE SHOP TO GRAB A FEW BITS! WHEN I GET BACK YOU NEED TO BE OFF YOUR GAME OR WHATEVER IS MAKING YOU BE SO LOUD UP THERE! IT'S A SCHOOL NIGHT!" She yells.

Your face flushes red as Shelly playfully nibbles on your hickey, as you call back "A-alright Mom! S-see ya in the mornin'!"

You hear the front door open and slam shut downstairs as Shelly brings her face above yours. Her hair is a tangled mess that seems to cover you both in a small jungle of it, her face red and a look of pure adoration in her eyes as a grin slowly creeps onto her face. "Just- me and y-YOUUUUU! N-now lover boy~" She moans. You don't even bother to respond as your grab her hair and **** her into another kiss. Her eyes widen for a moment, before drooping as she melts into the kiss, and before long let's out a loud moan as you feel her convulse around your cock, which you realise is her reaching orgasm.

For a brief moment, you considered stopping to give her a breather, but then your resolve hardened as you pulled your lips away from hers. She looks down at you, her face crimson with a goofy smile on her face, and she looks like she's about to say something when you suddenly flip the pair of you over and she lets out a small shriek of surprise. Your cock slides out of her briefly as you push her into the doggy style position, pulling her knees up so that her ass is in the air, as you press a hand to the back of her head holding her face against the pillow below and press your cock into her well wetted snatch and begin to piston in and out at an almost inhuman rate as her moans fill the air once more, now slightly muffled by the pillow in her face. She turns her face over, and over the top of her beautiful round globes you can see a look of pure ecstasy on her face as she moans loudly, unable to form words. You don't acknowledge this, just slap your hand down hard on her pert backside, eliciting a cry of surprised pleasure and pain, as you continue to piston in and out, drawing closer to the orgasm you so desperately need.

You continue this, and eventually you feel the pressure in your cock build up, as you pull out and watch string after string of your pearly white cum plaster itself over her ass and back, before falling back on your arms, panting. Shelly's knees buckle beneath her, as her ass falls down and she lays limp on the bed. You realise amidst your lustful pounding, she had cum a second time and now looks as if she hasn't a thought in her mind. You move yourself to behind her, as you pull her into a cuddle, her rear pressed against your slowly falling member, and snuggle your face into her neck. She seems to perk up a little at this, as she weakly rubs her ass against you and you chuckle slightly. "I think that's enough for tonight sis, we've been at this for-" You turn to your clock, only to see that it reads "11:48", and you swear under your breath. "Okay, mom's bound to be back soon Shell, we need to get you back to-" You say as your turn back to your sister beside you, only to find her asleep, drool pooling onto your pillow and a look of bliss on her face. You can't find it in your heart to wake her, so your carefully stand up and lock your door, before climbing back into bed and reassuming your spooning position. Your mom surely won't notice right?