This happened to me when I was 30. I live in Australia and have always enjoyed a good orgasm and a bit of exhibitionism.
One day I saw an advertisement asking for a female to pose for an erotic art class. The pay was good and it tickled my exhibitionist fantasy.
My first job was to pose for a group of 10 men in an art class with a vibrator in my pussy making it look like I was masturbating. During the class I noticed that a couple of the men were playing with themselves through their pants. This is another huge turn on for me - to watch men masturbate. I was beginning to get wet and the vibe was slipping out so I had to push it back in. This movement got me going a bit and when one of the men exposed his hard cock and began rubbing it I found it near impossible not to jill off. The vibe was slipping out and I kept pushing it back in. I was so turned on that I soon forgot where I was and just started pushing it in and out with very obvious movements. I noticed that when I began this a couple more of the men pulled their hard cocks out of their hiding places and were masturbating in ernest. I couldn't hold back and began rubbing my clit and fully thrusting with the vibe until all the men were openly masturbating.
At first one of the men came and then a couple more then I was frantically going at myself and as I came I squirted, which I had never done before. I was one awesome orgasm and turn on as I watched the rest of the men furiously masturbating and sending streams of cum onto the floor.
I have been back on a number of occassions and each time masturbated in front of the men, and enjoyed it.