Forgive me for Sex at Home, Father! 1998

Directed by Yukio Kitazawa

Hidekazu is invited to the house of his young lover Ami. Sex immediately begins in her room, but Ami's father-in-law watches the whole thing. Later, Hidekazu is called by his father-in-law and visits Ami's house again, and is captivated by Ami's bewitching mother, Chifuyu. It's all a trick of Ami's doting father-in-law.