For strengthening family bonds, nothing beats an open-air bath. Things that can't be said in daily life can be spoken freely when naked together. The big-breasted sister carefully teaches her younger sister how to give a blowjob, and earnestly provides sex education for her cherry boy brother. In an atmosphere where anything can be discussed within the family, there are moments when the brother is asked to perform by his parents, leading to on-the-spot challenges. The outdoor bath, where family members can talk openly while naked, is a special space that opens both hearts and bodies, deepening familial bonds like no other.