I've had phone sex at work. Also used the work printer to send a girl tributes. Worked late once and projected porn onto the wall of the board room too
I've jerked off often at work. At one point I was even jerking in a lab (electronics) under the table. Frequently in the bathrooms in offices that I've worked in.
I used to have a private office and I jerked off in there quite a few times including some phone sex on company time. Oops naughty me.
I was also caught once. I don't mind being watched, I quite enjoy in fact, but would have preferred it to be by intent rather than to surprise the guy.