Humping can be for many reasons - perhaps something excited him. Twizzler used to hump Toffee when she got excited - Toffee tolerated it and it didn't last long - it was usually excitement over food.

There are a lot of reasons. I wouldn't worry about it. Powder humps Stickers if she gets in the litter box and he's too close, or if she runs around in a certain way cause he gets excited, or ... a few others reasons I can't pinpoint. Well, he tries anyway. She usually runs for the hills and he can't catch her. lol Some humping is normal in a bonded pair.

One of our boy buns who we think is considered the "top bun" in our trio does this every once in awhile also -- I think in his case it's too express his dominance because whenever he does it he's always a little overly feisty and pushy towards the other buns. They just say whatever and he goes happily hopping away.

Could be dominance. Especially if he felt the urge to assert himself for some reason.

My pair has been bonded for over 4 years and my male lop humps my female mini rex, at least once or twice a day that I see. This behavior didn't even start until several months AFTER they were successfully bonded. Sometimes she will scatter when he starts to chase, sometimes she won't and it lasts 10-20 seconds. Oftentimes he will be grooming her head or ears, then take a break to hump, and then go back to grooming her head. I don't know what it means necessarily, but they still co-exist happily.

Most of what i've heard is that they are showing their dominance...Snowflake doesn this to her stuffed animals, and my friend's rabbit did it to her (which was goofy since she's the dominant one...go figure). They aren't hurting each other, are they?