Dog Body Language-Mounting
When your dog either mounts another dog or stands above another dog by putting her front paws on the other dog's back, she's saying, "I'm top dog and don't you forget it." Mounting other dogs isn't just a male characteristic other dogs females do it too. Owners wonder why male dogs mount other males or why females mount at all, but mounting is usually a dominance thing. It rarely has sexual overtones.
Humping: There's sexual intent in this behaviour, even if the dog doing the humping is neutered. You can let them interact, as long as the subject isn't trying to hide (and, of course, providing your dog is not and unneutered male and the other dog is a female in heat). If he does it to a person, break his focus suddenly by making a loud noise to stop him in his tracks