It was our first family trip in a long time. However, my husband was at work, and my son didn't seem to be in the mood either... So I invited my son to a mixed-gender outdoor bath for the first time in a long time. My son's body had grown stronger and more manly, but maybe because I was naked, his crotch had gotten bigger... I was worried about what other people would think, so I had no choice but to calm it down with my mouth. Then, that night, my son came to me with his hard, erect cock...