Mother Ryoko worries about her shy only son. One day, she finds a sticky stain on her son's underwear and discovers her mother Ryoko's underwear in her son's room. Ryoko, who noticed that her son has her sexual troubles, gives sex education to her son with her own body. However, her son is fascinated by her ripe yet beautiful mother's body. She secretly attacks her mother who is indulging in her masturbation and forcibly strikes her vagina with a penis, but Ryoko happily accepts her son's growth.
