The son has a strange habit of secretly listening to his mother's toilet sounds. When he's caught eavesdropping, the mother feels an unusual excitement. She proposes a deal: she'll let him watch her urinate if he gives her a blowjob. The son happily agrees, and their relationship gradually deepens. On the futon, their intimacy escalates as the son runs his fingers over his mother's crotch. Soon, his tongue moves toward her anus, making her aroused by the sensation. Eventually, their relationship progresses to the point where they share bowel movements with each other.