My friend wears dog ears and tail around the house to help communicate and play with his dog. The tail he wears has wire in it so it can stay however its bent. He pulls it up when he's suppose to be alert and he pulls it down when he isn't. The dog acts differently to both positions to the 'tail'. The ears have wire in them too so when he perks them forward as if he's listening to something his dog raises her ears too. Once he barked out the window and she looked around then started growling and barking too. Does the dog really understand or is it just a coincidence that she's doing those things?