Azdaema asked: So I think a big stumbling block for me with this ship is that I very much adhere to the reading of the show that holds:
Quasi-Seducer!Azula (as seen virtually anytime) and Quasi-Seducer!Zuko (as seen in "The Waterbending Scroll") are not actually expressions of desire from them. Rather, this is Zuko and Azula trying to be intimidating by modeling their behavior off their father (circling, personal-space-invading, low seductive tones, etc)
When actually trying to flirt neither Zuko nor Azula acts anything like that. When Zuko goes on that date with a girl in the Earth Kingdom, or Azula flirting with that guy on Ember Island, they're both awkward disasters.
I'd be curious to hear you address this. (Or point me to some awkward disaster!zucest fanfic.)
That is a really good point and I'm glad you brought it up. While I understand that reading of the show, I disagree with it slightly for a few reasons (beyond my own bias).
Need to be in control: No one can argue against the fact that neither Zuko nor Azula know how to have "normal", healthy relationships with others, mainly due to how unequal 99% of the relationships in the Fire Nation are since imposing your own will over someone else's has become part of their culture. Both Zuko and Azula accepted being treated like mere tools/punching bags by their father, Zuko was constantly insulting Iroh over the smallest things and Azula full on threatened Ty Lee's life to make her join her on her chase after her brother and the Avatar - both were scenarios where desire wasn't a factor at all (thought I know many fans that would like to think otherwise XD)
However, during The Beach, we saw how both of them try (and fail) to deal with romance. Zuko was extremely paranoid that Mai was interested in another guy, for no real reason, and was constantly trying to intimidate her into either admitting to it or into saying she disliked the guy, even though she had clearly said she was completely indifferent to him. And Azula, after her kiss with Chan, decided, on her own and not giving a damn about his feelings on the matter, that not only would they be officially a couple, but that they'd dominate the earth together. Control is, more often than not, a major factor in all of their actions and relationships, so Azula wanting to intimidate Zuko in the bedroom scene (which she very much tried to do and succeeded at) doesn't automatically rule out the possibility of attraction.
Mixed feelings: While "I wanna fight/kill my sibling" is sort of these two default state, there are moments that show that they do have at least some positive feelings for each other. Zuko doesn't give a shit that Aang is going to kill Ozai, but seeing Azula falling "to her death" and then chained up and defeated after their Agni Kai quite clearly made him emotional, even if he tried to control himself. Azula's positive feelings for Zuko are so obvious I had to do an in length discussion of it in chapter 12 "Is Zucest just about sex?" Combine all of the conflicting emotions they have for each other with their need to control the other, and some scenes end up getting some connotations the writers weren't planning them to have... supposedly (I'll get into that in a bit)
Awareness and familiarity: Don't get me wrong, Zuko and Azula are two extremely traumatized, socially awkward teenagers who have no idea how to flirt (or how to fit in with people their age) but we also need to take context into consideration, especial when it comes to Zuko's date with Jin and Azula's interactions with Chan.
In Ba Sing Se, Zuko was outside of his comfort zone, away from home, in enemy territory, and so paranoid that he assumed Jin came into the tea shop so often because she knew they were Fire Nation, not because she had a crush on him or simply enjoyed their tea. And while he liked her and the date was nice, Zuko was very "stiff" and even looked a bit uncomfortable (not to say very uncomfortable) at some points - which is oddly simmilar to how he was acting during the bedroom scene (hell, Azula was quite clearly looking at him just like Jin did, as I pointed out in "The most important parallel in Avatar"). Finally, we cannot forget that, even though he was awkward as fuck during 90% of the night, Zuko did manage to do something kinda romantic by lighting up the place, meaning he isn't completely oblivious to the concept of flirting (which is proved by his relationship with Mai).
Now, when it comes to Azula, the poor girl has almost no idea how to flirt. Almost. Talking about Chan's sharp outfit shows she's got some of the basis down, like "say something nice" - the problem is that her concept of "nice" is very different than that of most people. She did sort of know what to do once Ty Lee gave her some tips... but she quickly reversed back to her regular ways - which once again shows that flirting/seduction has an element of control and intimidation for her. She probably doesn't always mean to act in ways that could be considered flirty, but that doesn't mean she is completely oblivious to the implications of, let's say, invading her brother's personal space and talking to him in a low tone while wearing nothing but a robe.
And since I mentioned Azula going back to what she knows, that leads us to another thing to take into account: the fact that Zuko and Azula quite literally knew each other their whole lives - meaning if they were to ever flirt with each other, it would probably look at least somewhat different than when they were out of their element. Azula was the one in control, so she was far more comfortable and confident than she had been with Chan, and Zuko was the one being intimidated, which explains why he kept his guard up. Once again, that "theory" is sort of confirmed if we compare how Zuko acted while flirting with Mai on The Headband versus how he tried to interact with her in The Beach - when he used a non-traditional, but very Mai-esque "You're so beautiful when you hate the world" he got her equivalent of an "I love you" when she told him she didn't hate him, but he tried to do more "normal" things like getting her a pretty shell it blew up on his face. He knows Mai since they were both kids, meaning he usually knows how to deal with her, just like Azula usually knows how to deal with him.
Intensity: While a lot of Azula's behavior can be explained by her copying Ozai, we need to remember that there's only so much he could affect, especially since her way of "intimidating" Zuko was far more touchy and incestuous than his, and lasted a lot longer. Azula gets close to people when she's intimidating them (see how she toyed with Aang in The Drill), but not as close as she did with her brother. The sole exception to that being Sokka on The Day Of Black Sun - but that is on somewhat shaky ground despite the accidental sexual tension since the first time she got close to him she was being launched by the Dai Li and he just happened to be standing a little bellow the direction she was launched at, and the second time had him pinning her to the wall (which is in character since Sokka usually goes straight at his foes to intimidate them while fighting), and as soon as she had her firebending back she pushed him away. On top of that, she was trying to distract him, Aang and Toph, meaning he wasn't her focus at all, and she ignored him on all the other times their groups were facing each other.
With Zuko on the other hand, she was going full force, like I said on my analysis of the bedroom scene. She played coy, stared at him in a very intense, weird way, circled the pillar on her bed, stretched in front of him, got on his personal space touching his shoulder and chest, and bit her lip while talking basically purring her words. That is all a bit too much for me to believe it was just about intimidation. And the touching gets even more suspicious when you notice Azula does enjoy and is willing to give physical affection - she hugged both Mai and Ty Lee after seeing them again, pulled Ty Lee close while comforting her and apologizing for her harsh words at The Beach... and put her hand on Zuko's shoulder while saying he restored his own honor to reassure him after he was feeling bad for betraying his uncle.
Intention of the actors/writers/animators: Avatar is no stranger to parallels. It also isn't a stranger to adult themes/jokes, fanservice, and ship teasing. For instance, even though they didn't end up together and were never canonically interested in each other, there was A LOT of hints/teases of Zutara - dude fucking took lightning to the heart for her.
Just like the writers and producers were aware of Zutara, Tokka and many, many other ships, they were also aware of Zucest and even jokingly shipped Azula and The Blue Spirit at a panel. The animators habit of sexualizing the characters speaks for itself, so I won't even go into that. Finally, Grey Delisle, Azula's voice actress is a Zucest shiper, has brought it up many times, asked people to send her fanart and fanfic of it, created the phrase "Zucest is best cest", and has full on said she voiced the scene as if Azula was trying to seduce Zuko, - which regardless of whether or not the writers intended for the character to be doing, means that there is a very strong incest subtext to the scene and that, in a weird way, "Azula" herself confirmed her motives to act the way she did.