Kaikan onanie: Niizuma-hen (1993)

This softcore effort from cult pinku-eiga director Hisayasu Sato concerns the perfect couple. Of course, they don’t know that they’re the perfect couple because they each keep a “terrible” secret from the other. This prevents them from enjoying a normal sex life. The husband is impotent unless he can watch another couple having sex, and the wife pleasures herself to thoughts of being raped while someone else watches. Eventually, the voyeuristic husband and the exhibitionist wife confess their secrets to each other and realize how silly they’ve been when they were clearly made for each other.