Let me explain you something what you must probably have supposed yourself. That what you can see on the sports ground (a fight) is not what is in reality for your dog and definitely not what is in his head.
During the fight there is a competition between a decoy and the dog. The prey is not a sleeve, but the decoy himself. The decoy represents a buffalo, and the sleeve represents a piece of meat with fur ripped off him. You are - a member of the pack, wolves hunt in packs, when one bites - the other one distracts the victim and gives certain signals to his companion. That is the formula. When you send your dog onto decoy - he will hold as long as "the piece of meat" is not going, but ready to release. But if you start walking towards the decoy - your dog would squeeze his jaws harder, because your close proximity would indicate that you are going to join him in biting, so you would rip "the buffalo" apart together. Everything dog does - is an instinct, everything dog learns - is unnatural for him, he learns to fight together with another animal, that is human, that is you. Your task is to teach him fighting your way. But for the reason it could be helpful for you to watch videos with wolves hunting, try to understand their cooperative movements.
When you play with your dog you just help him to strengthen his jaw muscles. Thus young cubs pull a deer leg out of each other's mouth when prey was brought back to the den, thus two puppies play with a stick or some toy, they want to have it each for himself only. If your dog drops this "piece of meat" - he does it for you, say, he sacrifices precious object for the stronger, because he minds you stronger than him and because he loves you. In such plays a dog who minds himself equal with his master would hold for longer, play more vigorously. And, the dog who minds himself stronger than his master - would never give up before he grabs the object all just for himself. It doesn't mean that the dog will behave in the same manner with a decoy.
Please, don't worry. You simply need to work with professionals. It is time to join the club.
Last edited by David Taggart; 04-06-2015 at 10:10 PM.