That's too sad for me to laugh at. I actually had something sorta like this happen to me, where I was the "victim". I was in a packed streetcar with a few friends, headed to the CNE to see the Blue Angels. I was up against the side, standing up, while this chick in front of me kept involuntarily moving her ass into my torso (she was getting pushed as more people crowded into streetcar). I got a semi-hard on but tried to think unsexy thoughts, lol. This lasted a whole 15 minutes. I wonder if she felt something growing behind her. My buddy was jealous and said "hey, you got a free lap dance - be happy".
Wow, this is both, hillarious and disturbing at the same time. Was he expecting a hand job with out her noticing? wtf