One night, the couple's activities are seen by their son and daughter. - And the Shota family's distorted sex education began with daughter Mari's words, ``Does sex with your father feel good?'' - In the bath, fellatio is taught, and in the children's room, a mother gives sex lessons to her son, and a father gives sex lessons to his daughter. - Then, in front of their father and mother, they put into practice what they had learned together.