The sister, her big boobs heaving with arousal, sits her brother down and straddles him, her big ass rubbing against his cock. She's been watching him grow, his cock now a mouthwatering sight. She grinds on him, her pussy wet and aching. "Fuck me," she commands, guiding his cock into her tight hole. He groans as she takes him deep, her pussy stretching to accommodate his size. She fucks him hard, her tits bouncing, until they both cum, her pussy filled with his release.