And I'm a guy.
It was done in what is supposed to be a more playful, male way... like a couple steps down from getting a noogie or snapping towels in the locker room, if that makes sense. He literally snuck int my cubicle and put his big meathook hands on my shoulders (and I'm by no means a small guy) to ask me if I was joining everyone else for drinks after work. Which I never did since I don't drink, and aside from a couple of fellow programmers, I didn't care to deal with my co-workers more than I needed to. Not that I wasn't friendly, etc. but once work was over, I had better things to do.
And I'm not saying, "Oh, boo-hoo, men also suffer," but to agree that it's a dominance thing, and it happens to women waaay more. This particular manager was a big guy and big on physical dominance - he had no problem with bloodying your nose during a friendly game of basketball over lunch and would often lose his temper if other managers (especially the women ones) didn't let him have his way. He was eventually fired, but it took too long in my opinion, and I'm sure whatever business-lingo excuse they put in his file translated to, "Total dickhead."
TlalocW