Mother Miina divorced her husband and raised her son Kouta on her own. A dedicated and loving parent, she poured her heart into raising him, but as Kouta grew, she failed to notice his awakening awareness as a young man. One day, Kouta's curiosity shifted from studying to the female body, and he began playing tricks on his sleeping mother. This incident made Miina realize the urgent need for sex education, so she decided to personally teach him the fundamentals of sex using her own body. With maternal care and meticulous attention, she instructs him on how to touch breasts, handle a woman's genitals, and even how to penetrate. This is a one-of-a-kind, hands-on sex education lesson only a mother could provide.