Tomodachi no Haha wo Okasu to Iukoto  

  友達の母を犯すということ

Rou keeps an affair with Suzuko, his classmate's mother. Yes, they secretly have sex once a week. One day, Rou and Suzuko are witnessed by Iori, Rou's neighbor, when they get out of the hotel. At first, Rou feels sorry because Iori takes a good care of him. There is a heavy atmosphere between Rou and Iori.... Rou finally decides to shag Iori as well....