Mounting behaviour often creates a lot of embarrassment and concern but it is something that most young dogs attempt from time to time, as Claire Arrowsmith explains...
(Q) I was advised to have my one-year-old cross-breed castrated, hoping that it would stop him trying to mount everything in sight. It was particularly bad when my children played with him. He was castrated three months ago but it doesn't seem to have made any difference.
(A) Behaviourist Claire Arrowsmith says: Mounting can be observed in very young puppies and neutered dogs - we can see that in many cases the behaviour has little to do with a sexual urge. Most often it's due to the young dog trying out new actions and exploring play possibilities.
Dogs who become overexcited often mount and this is often the reason for it occurring during play with children. While neutering is a solution for excessive sexual behaviour, it won't reduce the learned behaviour or prevent your dog's excitement or frustration during play. Therefore it's important to make sure that you follow a consistent pattern to teach your dog how to respond more appropriately.
Firstly, it's helpful to think about how you and the children react when your dog mounts. Many dogs are accidentally encouraged to perform this behaviour after getting lots of attention when they first tried it. Some owners think it's funny at first, while others get flustered and try to shake the dog off, inadvertently creating more excitement. Others focus on the dog telling him off. In each case, the dog is being given more attention for mounting and therefore, the behaviour repeats.
You'll need to supervise him closely when he plays with your children. If you suspect that he's becoming too excited you should call him away and praise him. Allow him to calm a little before letting him play with the children again. This will allow him to learn to play appropriately. If you see him preparing to mount you must distract him, but make sure your voice is happy rather than angry. If he obeys then praise him and redirect his focus on to a game with his own toys, or perhaps some quiet time in another area.
For the best results, everyone your dog targets for mounting should be told to stand still, not to talk to him, not to try to shake him off, and to make little fuss. This reduces the excitement of the action. Often the dog will give up, especially if a better game is offered elsewhere. Of course, if the children are too young to manage this or are worried by his actions, you should calmly and quietly take hold of his collar and gently walk him away.
He shouldn't receive any attention when he is mounting since this will only lead to more reinforcement and excitement. If you are consistent and make sure that your dog has plenty of opportunity for exercise and appropriate play, it's very likely that this undesirable habit will be resolved as he matures.