My dog always acts aggressive when he has a bone, he won't give it up for anything. He isnt aggressive at anything else, this is the only problem. i read online that i should teach him to drop things for treats such as toys and balls so he becomes use to dropping things on command but he regards his bones too highly. how can i train him to be able to take them out of his mouth. The only way he drops them is if i put him into the submissive position (him lying on his side with my hand on his neck and side) and eventually he just lets it out of his mouth but i dont want to do that i want to just take it out whenever i want.