I have a female and male dog and the only time I have seen Cherry mount Parker is if he has charged past her rudely when is overexcited with a toy in his mouth. She will bark complainingly at him and mount him sideways for a few seconds. It is definitely not play in her case!!

My name is Gemma and i also have a humper!

My neutered male dog tends to do it, its often him trying to calm down youngsters or to engage play. He seems to favour labs as they are always daft and giddy but big while still being very young. But he also does it is a dog is tense, which often results in a bit of a squabble. Touch wood he has never hurt a dog, but I do really really wish he wouldn't do it.

Suppose in both ways he is trying to get the other dog to relax, a bit of a 'hey I'm here, you just all need to chill!'

I have never met an owner who isn't bothered, and most dogs really don't like it either.... Maybe that's just the area I live in.
I think if they didn't mind as much I probably wouldn't either.

Honey humps Kane quite often, never when she's over excited though it goes like this:
wrestle wrestle wrestle, Kane decks Honey, Honey see's her ****, quick burst of handbags at dawn, ending with Honey humping him and look of "for god's sake, just hurry up" on Kanes face lol
but she isnt dominant over him as he often stands on top of her when we have other dogs in the house, as if to say,"my girl" and she lets him. think with many things in the dog world its just swings and roundabouts

Jessie, my spayed BC bitch, often humps Roodee, the Cavalier, she is worse since she was spayed, his expression is hilarious.

It is quite normal & has nothing to do with dominance, poor Wukee, who is very much the omega dog, humps the cat !! Pretty dog, just a bit confused !

My young collie bitch humps my pug every night just before bed! my pug likes to hump my ragdoll cat (both male) my papillion bitch pup likes to hump my dressing gown!!!!!!!!!!!!!