Hi, my mom who lives with me adopted a 2 year old Chiuahua/S?it-Shu mix rescue 1 week ago. He is very attached to her already. We are trying to have my mom discipline him when he barks at me(he is very afraid of me,for no reason, I walk him and give him treats and pet him when he allows me to), by keeping him on a leash and having my mother tug on the leash when he barks at me. Well, now when she grabs the leash he goes to bite her! Help!!