It doesn't look like he's gagging or anything.... Maybe there's a way to like, super-clean..? I just kind of swish it up there with some soap and water and rub, am I doing it wrong?!

[ Because there's no way that someone would be licking that if it wasn't clean, right?! He's with Zuko on this one! taichi's not like top-tier cleanliness guru but he's not going to go sticking his tongue up a bum. And now he's worried he should've been cleaning his bum differently, but it's not like anyone teaches you that part??? ]