J., alone and horny, browses explicit photos on his phone, his hand sneaking into his pants to stroke his growing erection. His sister, unaware, enters the room, catching him mid-act. Angered, she scolds him, but their argument quickly escalates. As she storms off, J. can't help but notice her round ass swaying. Later, she returns, calmer, and admits to her own frustrations. She confesses to masturbating to his photos, and they decide to explore their mutual desires. J. watches as she touches herself, then she begs him to fuck her, hard.