Meiki Hitosuji(1989)

A man once worked as an assistant director at a film studio. He had a past in which the master director he worked for taught him about exhibitionism and even homosexuality. Since then, the man was unable to find a girlfriend. One day, that a hookup said she was going to return to the countryside and get married properly, so she wanted to break up. The man was surprised, but she had already prepared another friend for him. He starts dating the girl, but she is also quite a pervert, and suggests having sex with him in front of his bedridden father at home. The man agrees and goes to her house, only to discover that the bedridden father is the famous director...