-
It sounds like to me that the pit bull was displaying defense of his territory on the couch. And being able to stake claim to wherever he wanted to that he was the dominant figure in the household. When the visitor tried to get the dog to move he jumped at him to show this is mine and you can’t have it. And when the owner, who was not established as the leader, broke them up was bitten because now the aggression has been redirected. And being a pit bull, with their strong jaws and bite force, to get the dog off the visitor there is no telling how she managed that without causing some kind of pain to the dog.
