We have 3 dogs at our house, a 14 year old shih poo (female), and 2 small terrier mix’s from the same litter who are 9 (1 female and 1 male). The female terrier is very submissive to humans and other dogs. The male is submissive to humans but is very aggressive to other dogs that are not ours. He has attacked the neighbors dog twice now and both times the neighbors dog was running from him and not fighting back. Recently my son and his dog, a Carolina dog, has been staying with us a couple weeks every couple months. Our male terrier dog was not a big fan at him at first and would start fighting him out of no where. We suspected it was him getting anxious and trying to protect his sisters. We corrected him and he hasn’t had a fight since the summer. My son is home for the holidays now and noticed whenever our male terrier starts showing aggressive behavior (growling, long stares, tense stance) our female terrier will start correcting him. Which doesn’t help much because it causes a bunch of barking and more tension in the house. We don’t know how to stop this correcting because it feels like she is adding more fuel to the fire. Any suggestions?