Things don't seem to be going well between Rin's son and his girlfriend. Rin realizes that the root of the problem lies in his lack of sexual prowess, so her girlfriend offers to act as a coach and provide her son with intense sexual training. For the sake of her son's happiness, Rin uses her mature body and skillful technique to provide passionate guidance to her son. However, Rin's hard training eventually drives her son's libido wild...