Shinoda Yuu's husband is physically weak, and every time he fights with his wife, he can't get an erection. The father-in-law is constantly urging to have a grandchild, so the couple is trying very hard to have a baby.
Once when her father-in-law squeezed her shoulder while tired, Shinoda Yuu's husband suddenly entered. Seeing the scene where Dad was massaging his daughter-in-law, her husband Shinoda Yuu suddenly raised her head and got an erection.
So Shinoda Yuu's husband has found a way to help him get hot. He asked his father to have sex with his wife to help him regain his senses.
But the first time created the premise for the second, then the third. Father-in-law and daughter-in-law then surreptitiously played sex with each other more. Maybe eating clumsy is better than eating rice?