Great pictures!!
They are both adorable!! I love pictures of giant dogs next to tiny ones!! Great danes are my favorite big dog breed, they are such great dogs!!! If I had the room, I would have one right now, but I just don't have the room for one.
On a more serious note...
I would never let my dogs continue on humping dogs, I hate the humping and they know they rules and abide by them. I am currently babysitting two dogs, a terrier mix and a shih tzu. The shih tzu, which is a female, is constantly humping my dogs. Her owner never discouraged it so at her house she is allowed to do it anytime she wants and to anyone she wants. It has been frustrating and while I am always happy to babysit dogs for friends or relatives, I will be glad when she goes back home. She knows it is not allowed here and that we absolutely hate the behavior. She is not as bad now, but once she goes back home, she will start all over again, it is a shame.
The result of her trying to hump the dogs has resulted in my little one being horrifed of her and will run and hide the whole time because she does this. My other dogs, the bigger ones, have gotten in several fights with her because of this behavior. It is a dominant thing and if we did not have a good control over the bigger dogs, they probably would have severely hurt her or even killed her.
After all these dogs are the dominant ones as they should be because they are the strongest and biggest and I would probably do the same thing if I were in their position. When we first brought her here that is all she did, she could not play or anything else, just try to hump the other dogs.
So IMO, humping (especially if it is a dominant thing) should not be allowed, it only causes more problems. Just think if you took your dog somewhere, store, vet, and she tried humping another dog, that dog probably would not like it and could attack her.