My pup is now 4.5 months and my older male is 7.5 years. The pup still pesters my older dog to death. My old male is very gentle and passive so he just puts up with her. Sometimes, most of the time, I just have to separate them because she is just relentless. He is 91 lbs and big. She is a smaller puppy. He will be taking a dump and she is riding him like zoro biting his ears and back. Hoping it eventually passes. Any advise?