A son-in-law has a problem with his wife's sex life because his penis is too big. His mother-in-law has noticed that something has been wrong with her daughter's relationship with her husband recently. It was supposed to be a difficult problem to confide, but he couldn't help but get an erection when he was in a situation with the two of them, and when she noticed, he got so excited that he got a super erection! "Mom...it's gotten so big..." The mother-in-law couldn't hide her surprise... The mother-in-law and son gradually got closer and decided to get started.