First time I've posted on this board, but I'm hoping for some advice. I have a very large mutt. For the most part he doesn't need much grooming despite his long hair, but when his hair sheds his butt get matted. I have noticed that when I brush it he gets really nervous. The vet recommended using a slicker brush, but he can stand it. I use a rubber brush which he is OK with until I get to his tush. I'm thinking he needs a tranquilizer, before I do it. I don't want him to be traumatized.