Next summer, I will be going on an overseas trip with my good friend and his wife. - We were planning to go diving, but since I was the only one who wasn't good at swimming, I decided to secretly go to a swimming school. - At the school, I was working one-on-one with a male instructor, and it had been a long time since I had had any contact with a man other than my husband, so I couldn't control the tingling in my body, and I ended up masturbating in the locker room. - I had no way of knowing that my appearance would be secretly filmed, and that I would start taking sex lessons using the video as a material...