I take Zoe to the dog park almost every day (I wish we had a yard, but we don't, and there's no where else close to let her run off leash). Every single time we are there a male dog humps her. I let it go once, but if the owner allows it, or ignores it, it really bothers me. I used to ask the owner of the horny offender to please pull their dog off, but today I'd had it. Some huge mixed breed kept humping my little dog and the owner did nothing- he thought it was just fine "dogs will do that" he says. The third time it happened I went over myself and pulled his dog off mine saying sternly "OFF my dog!" I told the owner once is not a big deal, but repeated humping is just rude. He leashed his dog and left. So there.