In the dimly lit bathroom, the scent of soap and steam fills the air. The sister, unknowingly, is the subject of her brother's lustful gaze. Through the slightly ajar door, he watches as she lathers her body, her hands caressing every curve. The water cascades down her back, drawing his eyes to her round ass. She bends over, giving him an unobstructed view of her pussy, barely concealed by the thin soap suds. His breath hitches as she reaches for her clit, rubbing it slowly, her moans barely audible over the running water. He can't help but stroke his hard cock, his eyes never leaving her as she brings herself to climax, her body shuddering with pleasure.