So you're walking your young dog in the neighborhood and see a neighbor stopped at her mailbox with her dog.
You stop to talk and in just a few moments your neighbor gasps. You look down and your enthusiastic male dog has grasped her dog by the neck with his front legs and is vigorously thrusting his hips towards her head. You yank your dog away and your neighbor stalks off without a word. Head hanging, you walk home as you berate your dog. Your dog doesn't care about your embarrassment; he's happy, prancing, tail wagging.
Embarrassing but Not Bad
Mounting is not bad; it's a natural behavior. Many people assume it is strictly a sexual reproductive behavior and that's not exactly true. Yes, a male dog mounting a receptive female dog is a reproductive action but most mounting is not for this reason. Males and females, intact or spayed or neutered, will mount in certain situations. Even though it's a natural behavior, however, most dog owners are either embarrassed about mounting, dislike it, or just wish their dog wouldn't do it. Thankfully, you can prevent or interrupt this behavior without causing your dog any harm.
Interrupt or Redirect
Don't try to stop mounting behaviors by yelling at your dog or correcting him by other means. Not only will these techniques not work, if your dog is mounting because of over-stimulation or anxiety, these punishments could make him more anxious and increase his mounting behaviors. Instead, interrupt him and get him interested in something else. For example, if he's mounting a toy or the family cat, interrupt him by making a noise (dropping a book to the floor, for example, or clapping your hands) let him see you as you pick up one of his toys and then walk into another room. When he follows you, praise him and toss the ball. Don't toss the ball immediately as he's still mounting, as that could serve as a reward for the mounting. Instead, distract him with the noise, pick up one of his toys, and when he follows you to another room, then he gets a reward.
Puppies will mount each other during play and this has nothing to do with reproduction. Nor is it dominant behavior; one puppy trying to dominate another. Instead, when one puppy jumps on another during play, that jumping action can trigger instinctive movements and the puppy will grasp with the front legs and the hips will begin thrusting motions. Both male and female puppies will do this. The puppy being mounting often protests; not because he (or she) is being mounted but because he's being pinned and his play is interrupted. The mounting puppy can easily be distracted, however, and the play can continue.
Not Dominance but Social Anxiety
Many dog owners assume that when one dog mounts another, the mounting dog is trying to assert dominance over the other dog. This commonly held belief actually hasn't been shown to be true in most canine interactions. In fact, the opposite is more common. An anxious or socially inept dog is more likely to attempt to mount another dog whereas the socially stable dog is less likely to perform this behavior. This may be more apt to occur when several dogs are playing and the socially inept dog will try and mount another dog (or his favorite playmate) in order to be a part of the group.
This behavior is usually self-limiting as the dog being mounted usually protests, causing the dog doing the mounting to stop; at least for the moment. However, the correction from a playmate can also cause the socially inept dog to become even more frantic about being a part of the group and he may then try harder to mount other dogs. If this happens the owner needs to step in and remove the socially inept dog from the situation and walk him until he calms down. Unfortunately, if he continues trying to mount while he's frantic, a dog fight could ensue.
Over-Stimulation During Play
Dogs who get over-stimulated during play in the house will often mount another dog. If another dog isn't available or if that dog won't cooperate, the dog may mount the family cat, a person, or a toy. This dog is usually easily distracted and can be redirected back to a play session. It's best, however, to learn when the dog is getting too excited and stop the play session before the mounting begins. Let the dog relax, calm down, and then let him continue playing.
Don't Laugh or Get Mad
Both intact or neutered dogs of both sexes will participate in mounting behavior if it gains your attention. A dog owner contacted me recently because when she has company, her young dog would drag one of her daughter's stuffed toys to the living room whenever they had guests and he would then vigorously mount the toy. All the attention (screaming, yelling, laughter, and activity) became a reward for his actions and he repeated it over and over again because every time he did it, he became the center of attention.
Instead of screaming and yelling, either put the dog in his crate when guests come over or keep him on leash so he can't go get the stuffed toy. If, on leash, he decides to mount something else, something close to him, simply remove him from the situation and put him in his crate. No screaming, no yelling; just remove him from all of the attention. If there is no attention then there is no reward.
Mounting behavior can be lessened for most dogs by making sure the dog gets plenty of exercise. Exercise tires the body and lessens boredom while relieving stress. Teaching your dog the basic obedience exercises teaches your dog to listen to you and to cooperate with your requests while trick training is fun and gives the dog the attention he craves. Exercise and training won't entirely eliminate mounting behaviors for enthusiastic dogs; but when used with prevention, interruptions and redirecting the dog, they will help.