Anon asked: How about some drunk!zucest?
I can picture them having a few (too many) drinks one night with the sailors (as they're leaving Ba Sing Se/going to the Fire Nation).
Zuko would eventually leave the group to be all angsty in his room (because of course he would). He wouldn't be able to do it for a long time, because he's little sister is apparently very affectionate when she's drunk, and for some reason she seems to want to be near him specifically.
At first, he's annoyed, but as his baby sister keeps touching his arm, hugging him, and kissing his cheek he starts to enjoy getting so much attention from her. And maybe it's just the alcohol talking, but Azula looks more beautiful than ever, and his shame is slowly disappearing. Azula didn't help by bringing him another bottle, that they're sharing as they talk and laugh together.
Finally, Azula moves on from just showing him affection to full on hitting on him, and Zuko just kisses her the second he realizes what she's doing.
The next morning, they both have horrible headaches and they're covered in hickeys, love-bites, and burn marks. Zuko's back makes it look like he was attacked by a wild animal. They can't look each other in the eye and the whole crew is uncomfortable - the walls of the ship are not sound proof at all, and both siblings are VERY loud and had quite a lot of stamina the previous night.