I need a little help! My 5 month old shih tzu is always biting on my 4 year old shih tzu! He bites her ears and her tail. He is not aggressive with her, its all in play, but the underside of her tail has lost almost ALL of its fur and I noticed she has a bald spot on her ear! He keeps ripping her fur out! Is there something I can spray on her that will keep him from pulling her fur... something that will not make them sick? We get on to him ALL the time and that just isn't working! I need help!!