The reason Nami Horikawa's teenage son can't concentrate on his studies is because he's drawn to his mother's large, swaying breasts and tight-fitting skirt clinging to her voluptuous backside. His focus constantly stolen by her curves, he's scolded for his poor grades—prompting him to desperately beg for face sitting in exchange for studying. Initially reluctant, Nami hesitates, but as she feels her son's face against her crotch, she gradually begins to moan. Responding to his pure, intense desire, she slowly becomes aroused, and their forbidden passion deepens the incestuous bond between them.