In the dimly lit room, the sister sits on the couch, legs crossed, waiting. Her brother enters, nervous but aroused. She pats the seat next to her, and as he sits, she leans in, whispering, "I need you, brother." She guides his hand to her ass, then stands, turning around and bending over, lifting her skirt. He hesitates, then spits on her asshole, rubbing it in. She moans, and he tentatively pushes in a finger. She pushes back, and he adds another, fucking her ass with his fingers. She begs for his cock, and he obliges, fucking her ass hard until they both cum, collapsing onto the couch.