I have a similar situation with my boy and my ten y.o. dachshund. As you can imagine an older doxie needs some protection from "the beast" My trainer suggested a squirt bottle (tight stream). At first I though yeah right? my boxer loves water. I can't even water in the yard without putting him in his crate. He will leap at the water and take a full forceful spray straight to the mouth biting at it the whole time. You would think he was a lab
Anyway I decided to try it and low and behold he hates the water bottle. Can't explain why, maybe because he is indoors?? It really works, and now after I say "LEAVE HIM" if he even sees me reach for the bottle he is gone. The one thing the trainer did say it pick your battles. Choose one or maybe two things that you will use the bottle with. If you use it for evey behavior that you don't like they will become indifferent to it. So I only use it for the "dog sitting/pawing" and I take it on our walks because of his problems with other dogs. It has worked well for this in that it provides that immediate distraction that is just enough to get us past the other dog. Once out of sight we are good to go!!