Nousagi had always been a pretty good actor, and his childish charms helped him out in that department. He balled up a small fist and raised it to his lip in a vulnerable fashion. Pouting, he sniffled and said, "Zuko was very mean...very mean to Nousagi," but, after his sad little charade, Nousagi couldn't help but giggle a bit at both his own ruse and Zuko's anger. The misplaced aggression seemed like such a meaningless waste of energy; to Nousagi, it just seemed silly. He had a temper of his own, but it wasn't anything like Zuko's.
"Yes sir, Captain Grumpypants, sir!" With this, he stood with his back ramrod straight and gave an overly-dramatic mock salute. Technically, he hadn't disobeyed either of Zuko's orders (besides the 'shut up' thing). He hadn't called Zuko Prince Firepants, nor had he referred to the group as Team Avatar-Hunter. Until further notice (which would be sure to come very soon, knowing Zuko), he was completely within his rights.
At that, Nousagi scrambled onto the back of the beast. It wasn't all that big but, then again, neither was he. He found a niche inbetween Jun and Zuko (he had a feeling that he would be keeping the two apart for much of this little adventure anyway) and held on tight.