Mother Yuriko was always attentive to her son's behavior. During her private moments—such as using the toilet or bathing—she sensed his presence and felt an inner unease and discomfort. One day, she realized her son was making advances toward her. Though she tried to flee in panic, she eventually gave in to his advances, and the two began a secret relationship. Whenever her husband was away, she spent more time with her son, who began directly demanding that she defecate for him. Gradually, Yuriko's body grew accustomed to this sensation.