Mount the owner to show dominance

Lot's of comments about dominance. This is an old erronous theory about dog behaviour based on a botched study. Dogs hump for many reasons, sexual is the obvious one, but also being nervous or poorly socialised.

What you should do is stop the behaviour, move your dog or theirs away and tell the owner to come get their dog.

If it happens in certain scenarios you can also stop it before the behaviour, so a common scenario is two dogs are playing, one dog gets overstimulated and then jumps on to hump, in that scenario you'd want to watch for earlier signs of overstimulation, wanting to stop, panting heavily, whale eyes, and stopping the play at that point.

Mount the owner.

"Oi, fuckstick! Mind your dog!"

Mount the owner.

If anything does something to your dog you don't agree with you are fully entitled to remove that thing from being near your dog. Grab the other dog by the collar and drag it away (not yanking, controlled movements).

If the owner of the other dog gets angry at this then state that you wouldn't have had to do so if they had the skills to keep their dog having good behaviour. Some times people need a verbal slap in the face to even start thinking about if they should do better. They won't agree with you in the situation, but it may help effect some change in their behaviour over time.

My dog was a big tall greyhound, and one time he was humped by another dog - a tiny Yorkshire terrier. It was clinging to his hock (ankle) and banging away for dear life, while my dog ignored it. Its owner and I were both laughing too hard to do anything about it, it was a ludicrous sight.

Sorry not to be more helpful.

Keep your dog away from their dog.

If at least one of them is fixed, at worst it's just a show of dominance. The bigger concern is for the dog humping. Those shows of dominance can lead to aggressive reactions from some dogs. If your dog isn't the type to react aggressively, it's not a big problem outside of any social awkwardness. The problem would be if that dog humped another that really didn't want it. Then there could be a fight. So it's in the owners best interest to discourage that behavior lest they hump the wrong dog.

All that said, even if your dog isn't the type to react and you just don't want another dog humping your dog, you should be fine taking some action. Either avoid the other dog or if that's not possible keep between your dog and the humper. Even physically holding the other dog away from yours should be fine. If the other owner takes offense to this, you can explain that you don't want their dog humping yours. At this point, they'll either concede and try to do better, remove their dog from the situation, or devolve into full Karen. Up to you how to handle that.

Ideally your dog should tell the other dog that it won't have it. Some times it takes longer than others for this to happen. For some dogs though this never happens

Hold their dog's collar and don't let go until the owner gets the hint. Just hold their dog in place. It's not hurting the animal but it's also not something the owner can just ignore.

Put yourself between it and your dog. Mounting is an act to show dominance. Be the more dominant dog.

Happens occasionally when I'm walking my dog.

My dog will let the other one know when she's had enough nonsense.

IMHO find a way to get over it and get over it.

Hump the owner. Assert dominance.

avoid them.

Mount their dog.

just let it go. it's not a big deal. dog's gonna dog.