My brother-in-law and sister were both very sexually active and inevitably had a physical relationship, secretly dealing with their sexual desires from their father-in-law. However, the brother-in-law's passive attitude led to growing dissatisfaction, and he began to wish that his father-in-law would take him. The father-in-law, who had been enduring and taking good care of his daughter, became aware of the relationship between the brother-in-law and his daughter, and he also eagerly waited to be deeply penetrated. They both enjoyed intense intercourse and were satisfied with each other.