Imaoka and Yokoyama are being taught by their friend's wife, Ayumi, in order to qualify as an administrative scrivener. Perhaps because she is a friend's wife, she is deceived by Ayumi's fragrant erotic pheromones. Imaoka, who has reached the limit of her patience, pleads with Ayumi, "If you can't have sex, at least just mouth!" Later, when Yokoyama finds out about it and can't concentrate on his studies, Ayumi gives him an erotic class.