Lovers are Wet 恋人たちは濡れた (1973)

Upon returning to his hometown, Katsu (OE Tetsu) starts working in a local theatre specialising in soft porn. He starts an affair with the theatre owner, but soon wanders away and meets a young couple. Erotic adventures await.

Important note for LOVERS ARE WET:
In certain scenes, there will be black boxes to cover explicit nudity. This is how the film was originally released, and it is an intentional artistic choice by the filmmaker.