Ai no nukumori

A middle-aged professor falls in love with a young girl and neglects his wife, who also seeks some sexual satisfaction. Nikkatsu studios offered a lot of 'pinku eiga' (aka erotic movies) in the 70s and this one plays more like an erotic drama. It doesn't have the more violent/S&M nature of some of their other films of that era. However, it has plenty of scenes with nudity and sex, with the usual camera positions that cover male and female private parts. Mari Tanaka (from similar films like The Naked Seven and Sex Rider: Wet Highway) looks gorgeous and the rest of the cast is also competent. Throw in some nightclub scenes with naked dancing and a whole 70s a-go-go vibe and the result is fine.