Mother's best friend

Natsuko, my mother's best friend since her school days, came to the Sato family to stay overnight. His son Satoru is drawn into Natsuko's charm, full of adult charm. When Natsuko learns that Satoru is still a virgin, she gently explains, "I'll be the first woman." Tension and confused, Satoru, who has successfully lost his virginity, ends up wanting Natsuko many times like a newly-learned monkey...