i have an 11yr old peek-a-poo. Toby has been with us since 8 weeks of age. He has in the past 4 years developed a strange aggressive streak. If the cat coughs, Toby lunges as if to attack. If a younger dog (we have 3) approaches me, he lunges aggressively at them. I have returned to our old obedience days providing a special “place” for him and keeping him clipped on leash to protect the cat and other 2 dogs but want to understand what he is thinking or reacting to. Any ideas?