I have noticed that in a lot of stories, authors who use the canine dominance of mounting tend to involve penetration. I wanted to find out if author's are simply using creative licensing to suit their stories so they can have Sesshoumaru breach Kagome's inner walls or Inuyasha in some stories, or do they really believe that dogs penetrate each other when exerting their dominance over each other?

Dogs don't actually penetrate each other when dominating one another. If they are, then they probably aren't trying to dominate, they are just having sex. What they are actually doing is rubbing their scent across the lower back of the other dog. For any other dog that comes across them, they immediately scent that this dog is of a lower status than another. If you see them rubbing their sex organs across the head of another dog, this means that the dog being dominated is mucccch further below their status. You generally see this with puppies. If you get on the ground with them, they will stand over your head (you see this more with the males) and just stand their showing they are above you. This is also why you will catch a dog growling if you are leaning over their head in certain situations, because they see you as setting up to try and put them below you. Females will mount other dogs just as much, even mount males, there's no penetration and the scent thing usually doesn't happen, it's all about the recognized motions in this case.

I just figured I'd put this out there maybe as extra information. I had thought about writing something funny based on head dominance too. I've had six dogs overall and plenty of dominance witnessing but I had never seen one actually penetrate another so curiosity won over.