Great thread, Widget!
I don't believe I have masturbated at work- though there were a few times I went to the bathroom to try because the need was so great.. however like one of the posters here (sorry! i forget whom!), I couldn't relax enough or get into a good position to do it.

BUT...

I have masturbated driving to and from work many times! I would carry my vibrator in my pocketbook with me! (And I would have used it at work if I hadn't feared it would have been overheard.)