It was a crazy idea, but he had no other choice when he had been treated in many places but still had no children. It's been 5 years since they got married, but Tsubasa can't have children because her husband has physiological problems, and she hasn't even had an orgasm yet. That is truly a disadvantage and misfortune for the wife who is promiscuous and always craves love. The husband was helpless and had to ask his younger brother, a big and strong guy who was good at fucking, to help his wife conceive. Tsubasa felt resentful towards her husband, not because he was doing incestuous things, but because he didn't bring his brother-in-law to see her sooner.