Mature Moms 11 - A Stepson Taking the Place of His Stepfather - Shuri Yamaguchi (2021)

Misako is a mother who runs a massage parlor. She lives with her son Takuo. Takuo had decided to go to Tokyo and go to a vocational school. One day, Takuo witnesses Misako having sex with a regular customer. Moreover, Takuo goes into a frenzy when he learns that the man will take care of his tuition fees. Jealousy that she doesn't want her mother to belong to anyone leads to sexual desire.