Her son, who lost his husband early and was raised by a single mother, is about to get married. Before that, mother and son decided to go on a trip to a hot spring. Looking at her grown-up son, Chisato saw her late husband. They went to the hot spring, had a meal, and spent a fun time thinking that this might be their last trip together as mother and son. Then they went to bed. In the middle of the night, I was woken up by my son's bad sleeping posture. Thinking that it was time to do it again, I tried to cover him with the futon. My son's yukata was open and his lower body was completely exposed, and I caught sight of him. His penis was half-erect, the exact same as my late husband's, and I was sucking it enthusiastically. I couldn't hold back. Before I knew it, I was straddling my son, enjoying a sensation I hadn't felt in a long time...