OK...so I'm a gossip monger...

I try to ignore Mr. Creepy as much as I can. It isn't easy when he's talking on the phone about "oh yeah put it in deeper" or "you like that so much don't you" or "is it one of those ones made of jelly?". I have to try hard to not pay attention to something that's literally happening AT my desk...
I need to report the problem to the right people, but what if the right people aren't around when the "offense" is happening?