Mother Sumika, dissatisfied with her sex life with her husband, masturbates every night to relieve her stress... Her son Manabu peeks at her and indulges in masturbation... One day, the son gets hold of some erotic oil lotion and offers his mother a massage, saying, "I'll help you relax after your daily chores." As he applies the oil to his mother's soft body, his crotch becomes so tense that it hurts... His mother begins to sob...