One night and two days of 1 night and left alone by my wife's sister who suddenly came over

While his wife was on a two-day trip with a friend, Akira was enjoying a leisurely life alone. Then suddenly, my wife's sister, Reira, came to visit me. However, in fact, Reira, who hasn't been doing well with her husband recently, has been planning to relieve his accumulated sexual desire with Akira. Without realizing that, Akira, who has completely lost his mind by eating home-cooked food, ends up going to take a bath. Then, for some reason, Reira also came in...