My corgi "Picasso" has started to develop aggression towards large dogs. If they get near his ears or face or try to stand over him, he goes psycho on them and tries to bite them. Now its not all large dogs but a lot of them. His face first looks as if he is scared and then "tries to get them before they get him." I have stopped him, but sometimes its hard to step in because he is so fast and just runs away. I have started to use a muzzle if i know we will be around large dogs. It has sort of helped but there is still a few large dogs that just rub him the wrong way. HELP!!!! Does anyone have this issue? Does anyone have suggestions??