another option, is for the human to get off the sofa and walk off. not a great option if you're in the middle of a really suspenceful movie/program and don't have ti-vo. (which is me) i have tried picking growly dog up and placing him or her off the sofa with mixed results.
Z and J will bicker often, usually about a spot on the floor that might have, or have had, or might will have, a molecule of food on it. I usually just ignore that b/c nobody ever gets hurt. Sometimes I put Z in the crate for a time out. J will also growl at P, but since she's 3.5 (he's 13) and is twice his size, I figure he's not going to hurt her and she's never growled. But you do have to know your pups and decide what YOU can tolerate.
