I love the post about Aang and Katara still having turtleduck instincts carry over once they're human again, but what about Sokka? I started rereading the story (again), and at this point I'm just imagining him seeing Zuko, lunging at him, and biting.
I believe referring to this post.
Yes, but I don't think it would be as overt as that. Not when he first saw him. My first thought when I saw this ask was of Sokka and Zuko arguing and Zuko pointing at Sokka. Sokka just instinctively bites the finger in his face and Zuko startles back (thankfully no fire) but Sokka doesn't let go. Then they both become aware of the situation. And it's just Sokka and Zuko standing awkwardly. Sokka still biting Zuko's finger and Zuko trying to work out if he should try to detach him like when he was a turtleduck. And neither of them having any idea what they should do to make this less awkward.
If Aang is there he definitely breaks the tension by squawking at Sokka and being upset because Sokka keeps telling him to stop acting like a turtleduck but here he is biting Zuko!
Katara is trying not to laugh while she whispers to Toph why this is funny. Toph makes it more awkward by laughing loudly.
Another thing Sokka does sometimes without realizing is expect Zuko to come looking for him. Just whenever Sokka is lost in the Fire Palace or skipping a meeting or something he kind of subconsciously is waiting for Zuko to find him and help him out or bring him a snack or something. He definitely isn't consciously aware of this. He just sometimes catches himself expecting to turn a corner to see Zuko searching for him or bribing him with treats.