With my wife anxious as childbirth approaches, her mother Lily travels to Tokyo from my hometown to support her. But my wife remains irritable and even bans me from masturbating, insisting I should not enjoy myself alone. Driven desperate by mounting desire, I lie to Lily that satisfying her daughter’s husband is a Japanese custom and ask her to take my wife’s place. Though bewildered and embarrassed, Lily gradually begins accepting my cock.