Marcus slammed the door behind him, sweat still dripping from his dark skin after the gym. At 24 he was built like a tank, thick arms and a heavy bulge in his shorts that never seemed to go down. His little sister Keisha, 22, was on the couch in nothing but a thin tank top and panties, her big brown tits spilling out the sides. She looked up and smirked. "You always come home horny as fuck, big bro."
"Shut up and spread those legs," he growled, kicking off his shoes. No slow shit tonight. He yanked his shorts down and his fat black cock sprang out, already hard and veined, the head shiny with precum. Keisha licked her lips and pulled her panties aside, showing her shaved pussy, lips already glistening. "Been waiting for this dick all day."
Marcus dropped to his knees between her thighs and buried his face in her cunt, tongue lashing her clit in hard, sloppy strokes. Keisha grabbed his head and ground against his mouth. "Eat that pussy, nigga. Suck it like you mean it." He did, sucking her swollen lips, shoving two thick fingers deep inside her and pumping fast. Her juices coated his chin and she moaned loud, legs shaking.
She pushed him back and climbed on top, grabbing his cock and slamming her wet hole down on it in one thrust. "Fuck yes," she hissed, riding him hard, her ass bouncing, titties swinging. Marcus slapped her cheeks and thrust up to meet her, balls slapping her ass. "Take that dick, sis. This black cock belongs in your tight pussy." She leaned down, tongue in his mouth, tasting herself while she fucked him faster, clit grinding on his pubic bone.
They switched fast. He flipped her onto all fours on the living room floor and rammed back in from behind, gripping her hips and pounding deep. The wet sounds of their fucking filled the room. Keisha reached back and spread her ass cheeks wider. "Deeper, Marcus. Fuck your sister's cunt like you own it." He did, pulling almost all the way out then slamming balls-deep, making her scream. Sweat ran down his chest onto her back.
He pulled out and shoved his cock into her mouth. Keisha sucked greedily, gagging on the thick length, spit dripping down her chin onto her tits. "That's it, clean your pussy off my dick," he said, fucking her throat. When he was close he pulled back, bent her over the arm of the couch and fucked her standing, one hand around her throat, the other rubbing her clit. Keisha came hard, pussy clenching and squirting down her thighs.
Marcus didn't stop. He pushed her flat on the couch, climbed on top and drove into her missionary style, staring into her eyes while he fucked her raw. "Gonna nut in this pussy," he grunted. "Fill my own sister up." She wrapped her legs around him and begged for it. "Do it, bro. Breed me with that hot cum."
He exploded deep inside her, thick ropes of cum pumping into her womb while she came again, milking every drop. They stayed locked together, breathing hard, his cock still twitching inside her flooded pussy.
Later in the shower they went at it again, Keisha on her knees sucking him clean before he bent her over the sink and took her ass, slow and deep until she was begging for more. By morning they were tangled in his bed, his cum leaking from both holes, already planning the next time the rest of the family went out. No guilt, just raw need and the best fuck either of them ever had.