A couple on a trip to a hot spring is invited to participate in a game by saying, "We'll pay for your stay if the wife doesn't get distracted by other men in the mixed bath!" The confident wife is confused by the erect penis that the man behind the game shows off! While worrying about her husband next to her, she can't help but glance at the big dick that comes into her field of vision! The wife, who has seen it 10 times, ends up having sex with the big-dick man she has been interested in! [Amateur couples] 4 couples included! !