I am staying in an expensive hotel on my own as I'm on a work event. Earlier this evening I went to the hotel gym and after a while on the running machines I thought I'd try out the sauna. I went into the sauna area and there was a main area outside the sauna door. The instructions asked that you should take a shower before entering the sauna but there was just one shower and nowhere to put your towel in the cubicle so I had to leave it outside on a hook in the open area.
I thought I would be ok as there was no one else in the gym when I came into the sauna area and I had my shower. When I came out of the shower cubicle, I opened the frosted glass door and went for my towel when the main door opened and someone came in. It was a young man, in his mid 20's maybe and I just stood there so embarrassed as he could see me nude in front of him. He looked sheepish and said he had just come in to use the shower. I got my towel and went into the sauna. Through the door I could see him strip off his shorts and tshirt and slip into the shower.
I could not believe that the hotel had this communal changing or shower area and knowing this attractive guy was in the shower next door got me really turned on. I slipped a hand under my towel and masturbated slowly. As he left, he looked at me through the glass door and would have seen me with my hand under my towel between my legs. Soon after that I came to an orgasm still turned on that a cute guy had seen me nude.