I'd have an indelible magic marker close at hand, to make the mark of Zorro!
ETA - Sorry. I don't know why people would do this at the office. it's inappropriate and could be considered sexual harrassment, whether it's same or different gender from you. Do you feel you can't speak up, your job would be endangered? You "should" try to handle it as simple and professionally as possible?

My last boss once came in to my cubiccle and like pulled UP his pants while he yelled at me (while I was sitting down), it was disgusting and humiliating and I wondered if he realized what he was doing. Again, I'm sorry for not taking this situation seriously. It feels horrible to be in a work situation where your bosses are nuts - it often replays feelings of helplessness from childhood abuse, it did for me, which makes it even harder to handle in the present. I have been out of it for a while, so I forgot. my (very very) bad.