LOL! I had a intact male cat who would do this-still laughing remembering him!!
So the Boogerman (yes that was his name) was cryptorchid, and we had to wait until he was pretty mature to castrate him so my vet could find the nut inside his belly.
My fat hairy dog (60lb collie shepX) was always growling and barking at the Boogerman in the bedroom. I hear the commotion, run over and yell at the dog "be nice to your little brother". Would happen every day, sometimes multiple times a day.
One day I'm sitting on the couch, fat hairy dog is by my feet. I watch the Boogerman slink over (in retrospect it was a sexy walk!). Booger slinks up to the dog, puts his arms on her neck and starts humping the snot out of the dogs shoulder!!!
Dog proceeds to growl and bark. Cat runs away. ****Light bulb moment*** I realized eveytime I'd hear the dog growl and bark at the cat, Booger was making sweet love to the Fat Hairy dog's shoulder. LOL.
So both of these pets are now deceased () but I used to have a maine coon named Max (15+, male) and my last corgi was named Bayley (female). They were both fixed and loved each other and would chase each other around the house. Every once in a while, Max would get this look in his eye and run up and hump the crap out of Bayley and then run away. It was actually pretty funny. We (my mother and I) always said he just couldn't resist that cute corgi butt
My cats still pee in the dog bowls and pee on the dog beds......the little cat just started to lay with one of the dogs and plays with her tail. Hoping for a little more love of the dogs from the little shi#%@ kitties but we shall see...
Yes, we have that goin' on here too! Our declawed and neutered rescue cat, Sylvester seems to be the instigator of most of the humping. He humps the other cats and gets really "into" any blankets or towels left around. He looks like he is listening to Barry White and everything is in slow motion as he romances the blanket or the other cats... My chihuahua, Badger humps Sylvester just about daily and also humps our corgi, Sasha. Our new chihuahua pup humps Badger - not sure if that will stop once she is spayed...
Personally I would not stop them unless the humpee is getting aggravated. They have their own social structure and aren't harming anything. If I had company and they were doing that, I would stop them (not yell, but just go get one of them or shoo them apart).
Just another weird thing that people without pets get horrified by lol!
When my 70 lb pit is lying on the sofa, the little boston jumps up and humps his head. Every Single Day. Pit just looks at her like "Really? You have to do this Again?" but never does anything to stop her.
I don't believe it has anything to do with "dominance". Most frequently, it appears to be a "self-soothing" behavior, so you'll see the Humpee doing it whenever things get exciting or the Humpee gets stressed about something- kind of like a child sucking on its thumb. Therefore the WRONG reaction is to increase the stress levels by trying to discipline the Humpee; instead, if you don't like it, you should gently re-direct the Humpee to an alternative soothing behavior, and then in future try to reduce the excitement level/ anxiety level of the Humpee before the Humpee breaks out in Humping.
Sometimes it's just about sex.
Technically, I think the one doing the humping is the Humpor and the one being humped is the Humpee.