We used to come on hot spring trips with the whole family every few years. This time, everyone was supposed to come, but they all got food poisoning, so I went on a long-awaited trip with just my mother and me. While soaking in the hot spring and enjoying the prepared meal, I drank some sake. My slightly drunk mother went back to the bath and came back, saying that no one was around, so she decided to join me. I was so excited by my mother's naked body that I couldn't say anything…