Rio Hamasaki, who is extremely popular for her beautiful big breasts and cute face, finally appears in this series! Moreover, as a mother, she seriously teaches her son about sex, which is the opposite of her usual slutty character, playing a moralistic and stoic role. For Rio Hamasaki fans, you can see her like never before! The highlight is the scene where the serious mother uses her own body to teach sex. While letting her son touch her body, she can't help but feel it, just like Rio.