Housewife Miki remarries and starts a new life with her son Junpei and her new husband. Junpei takes a strong liking to his stepfather, bonding with him as if they were a real father and son. As their relationship deepens, the husband begins teaching Junpei extreme sexual knowledge. Worried about this, Miki secretly decides to provide her own version of proper sex education. She passionately teaches her son everything—from how to kiss, the mechanics of the female anatomy, to how to penetrate—using her voluptuous, attractive body and big tits without reservation, creating intimate, loving moments of sex filled with warmth and affection.