This was the first time that I did it, but it was so good that I've repeated the experience a few amazing times.
I've always had a rush from masturbating where it was possible for me to get caught, but never anything in public. That is until I started going to a college five hours away from my hometown.
There's a rest stop about 45 minutes before I get to the town where I go to school and I'm usually driving back pretty late. One time when I was going I was bored and horny so I started jacking off in my car. The thought of girls that were headed back seeing me stroking my cock only turned me on more. So I decided to stop at the rest stop and finish what I had started. The road I was on doesn't have too much traffic, so when I pulled up at nine at night, there weren't any other cars there. So I put my erect dick in my pants and went in the guys bathroom where I started masturbating again. There's a full length mirror near the entrance of the bathroom and I stood in front of it, watching myself jack off. The thrill of someone coming in and catching me was turning me on even more.
Then I got the idea to go into the womens side. I was too nervous to walk through the lobby with my dick out, but anyone who was there would have easily seen it throbbing against my jeans. Simply being on the girls side was a huge turn on, but I started jacking off in front of the full length mirror on that side too. I kept imagining girls coming in and at first freaking out, but then joining in and helping me out. Then I had the idea to leave my cum somewhere for someone to find. So I walked over to the sink and almost immediately came. I closed my eyes so I couldn't see if someone walked in and came everywhere. The orgasm was so intense that my knees almost gave out. Not only that, it was one of the longest I'd ever had. When I was finished my semen was covering the edge of the sink, waiting for someone to find it and have their own experience.