[QUOTE=Brown Eyed Girl]
It’s a little tougher with the SO and kids though. They are the only ones he’s ever growled and nipped at. OTOH, he’s very protective of all us and has established the rule that there will be no horseplay or tickling of any kind. Apparently, he sees this activity as aggressive and will admonish whoever he deems to be the aggressor (i.e., the one making the other say “ouch” or “stop it.”) Although, the kids it’s totally unfair that I often get away with tickling as the dog usually takes my side, regardless of whether I started it.
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This made me giggle. I have a 5 lb Chihuahua who thinks he is a 100 lb wolf. Sounds like it when he barks, too. It’s always funny when new people come over, they are afraid of the barking beast until they see him 
Anyways, back to why you made me giggle – we play this game with Chili when we are tickling or horseplaying. Whoever is being tickled will cry out “oh, no, Chili! I’m being attacked!” and Chili will rush to their aid. He will nip (which in his case isn’t even so much a ‘nip’ as he puts his open mouth on you, kind of a warning – “I could hurt you if I wanted!” – I am serious when I say I think he sees himself as much bigger than he is!) and will continue “helping” the victim until the “attacker” quits. It’s hilarious.
I will say that we have had a few instances of dominance issues between him and my son. We got Chili when my son was only 3, so they’ve pretty much grown up together so far. Niq (the son) is a very non-violent kind of guy so he has a hard time with the sharp tone needed to back Chili into his place – I usually have to step in if I see Chili acting like he thinks he’s top dog. It’s never anything major, but I refuse to allow it at all.