Ryoko, the mother of a boy who lost her husband at an early age, has been raising him with care. One day, he comes home after being bullied because he doesn't recognize a pussy mark drawn on his face. Feeling sorry for him, Ryoko decides to use her own body to teach him sex education instead of his father. However, her son's Kokoro knows no bounds, and she even allows him to penetrate her! A bad mother who feels a sense of guilt at the sight of her son's cock, but still gets aroused!