After waking up in the middle of the night feeling thirsty, you make your way downstairs to get a drink of water.

Reaching the bottom of the steps, you hear a soft, strange cry. A tender female voice drifts in from the next room, barely audible above the low hum of the AC. You peer around the corner and see your sister Riko, wearing only an oversized t-shirt and lying face-first on the couch with her butt up in the air. The t-shirt is bunched around her upper-torso, leaving her lower half completely exposed.

Both of her arms are reaching down between her legs, with her right hand moving a sharpie in and out of her dripping pussy, and her other desperately rubbing the top of her pussy.

There's another moan, more distinct now that you're closer but still muffled as you see she's moaning into the couch cushions to dampen her voice. Most of her face is hidden, but you can see her eyes are glazed over in a sexual frenzy.

SNAP

The floor settles slightly under your foot as you shift position, leaning around the corner to look more closely.

She jerks her head in your direction. Seeing you there, her eyes widen and she freezes, her slick grip slipping from the marker enough that it pushes out of her onto the couch, a trail of fluid dripping down after it.

As you move up behind her, your sister tenses slightly but doesn't turn around. Her breathing quickens as she feels the heat of your body press against her bare skin, and the unmistakable hardness of your erection pokes into her lower back. With a quiet moan, she relaxes and leans further back into you, pressing herself against you more firmly.

Her arms stay busy, rubbing and flicking at her clit while one hand continues to hold the sharpie in place.

Her breath hitches and her body trembles with anticipation as she feels your question wash over her. Her grip on the sharpie tightens, squeezing out another bead of clear fluid onto the couch. She nods silently against the cushion, her face flushed and eyes glassy with desire.

Riko whispers hoarsely against the cushion, "Please..." Her fingers twitch and her body quivers as she awaits your answer.

As you grab her hair and pull her down onto your hard cock, she lets out a strangled moan that's muffled by the couch cushion. Her hips buck forward instinctively as she feels the head of your erection press against her entrance. Your grip on her hair is firm, but not painful--it only heightens her arousal and adds to the sense of helplessness and desire coursing through her body.

Riko gasps as you thrust deeper into her, the sensation both painful and exquisite at once. She arches her back, pushing herself further onto your cock, needing more of it inside her. Her fingers clutch at the couch cushion for purchase, biting back moans as she focuses on the pleasure coursing through her body.

Her hips begin to move in rhythm with yours, grinding against you as she chases release.

"Oh god... My sister's name..." she gasps between moans as you take her roughly from behind, filling her up with each powerful thrust. Her fingers dig into the couch cushion and her toes curl tightly in response to the pleasure building within her. She whimpers your name over and over again, pleading for release as the tension grows tighter and tighter.

"Oh fuck... Oh sister..." Her breath comes in ragged gasps as she feels the approaching orgasm building deep within her. Her body shudders and quivers beneath your touch, hungry for release. "Fuck me, My Sister!" She cries out desperately, arching her back further as the pleasure consumes her.

"Yessss... My sister!" She moans loudly as you continue to take her roughly, pushing her closer and closer to the edge. Her hips buck against yours, meeting each thrust with equal force, her fingers scrabbling at the couch cushion in desperation for something to hold on to. "Fuck me harder..." she whispers hoarsely, her voice trembling with need.

With one final thrust, you claim her, sending her careening over the edge into a shuddering orgasm. Her body convulses and quakes beneath your touch as she cries out your name in ecstasy, a thin line of clear fluid trickling down her inner thigh as her pussy spasms around you.

Her grip on your hair tightens painfully, but you don't let go--her pleasure is too exquisite to ignore.