The Cornered Mouse Dreams of Cheese

Kinky Kyoichi is a serial cheater and makes love to different easy women. The salaryman meets with an old class-mate from university called Wataru. Surprisingly, or not, he is an investigator hired by Kyoichi's wife to look into the husband's infidelity. However, Wataru has a sexual offer of his own for his old school-mate. (imdb)