Once Zuko started paying attention to the people around him again, he gave explicit orders for the guests to calm down, and his guards were watching them all like a hawk. Luckly, the situation didn't escalate much - though his sister certainly tried to get on people's nerves. After making a ton of sarcastic comments to their family and his friends as they all awkwardly celebrated the news, or rather, their happiness about it, she politely 'suggested' that any of the other guests who wanted to do the same should come to their table to talk to them for a bit, knowing they'd have to do it since that simple 'courtesy' that nobles offered each other and to royalty on those moments was pretty much an implicit rule. The young Fire Lord knew this wasn't the wisest idea, but he couldn't help but to go along with it. Azula deserved to enjoy herself.
Bumi, of course, was the first to congratulate them and the only one besides Toph, Ty Lee and Kiyi that seemed to actually be 100% okay with the situation. The other guests however, were clearly very uncomfortable and appalled, despite trying not to show it, and Zuko could see their eyes widening every time he and his sister so much as looked at each other, and their jaws dropped whenever he took her hand, put his arm around her, or kissed her cheek.
The noble families that had tried to have Zuko matched with any of their daughters were particularly scandalized, especially because Azula made a point of feeding him grapes or have him feed her some cherries as they talked. When Mai and her mother came to talk to them, probably because Mai was already sick of having to deal with so many people and was making sure to talk to the actual royalty so her mother would have no excuse to keep her when she inevitably tried to sneak off, Azula simply sat on his lap and started whispering and nipping at his ear, lacing her arms around his neck. The young Fire Lord was pretty sure his entire body had turned red.
When they turned away, Zuko grabbed his sister's face and made her look at him "Don't you think that was a little too much?" his annoyed glare and irritated tone only seemed to amuse her.
"I have no idea what you're talking about, Zuzu"
He scoffed and leaned in to whisper in her ear "If you had gotten any more territorial you would have ended up either riding me or sitting on my face"
"Oh, and you would just hate that, wouldn't you?" she asked, subtly rubbing up against his hardening cock, and Zuko had to fight back a groan "I'm just taking care of what's mine" she gave him a quick kiss before going back to her seat. Zuko failed to hide his disappointment and Azula chuckled.
His sister didn't tease him again for the rest of the night, mostly because Zuko's friends decided to go back to the table and distract them by talking about literally anything so they wouldn't end up making the night even more uncomfortable for everyone else. Still, they were pretty clingy and loving the entire time. Eventually uncle Iroh came back to their table, looking absolutely wasted, and started rambling on and on about the importance of family and how much of blessing children are... as well as saying over and over again that he didn't understand their relationship at all. Ikem asked some servants to the 'tired' (drunk) general to his chambers, then congratulated them yet again, and Ursa and Kiyi did the same. After a few hours, Azula started getting tired and didn't talk as much, and ended up resting her head on his shoulder, making him smile.
Once the feast was finally over, Zuko basically had to lead Azula to their bedroom as she was already half-asleep. He took off her shoes, then removed the flowers from her hair as he freed it from the top-knot. After spending a lot of time removing her make-up, he helped her off her clothes and handed her a sleeping robe. When he was ready to go to bed as well, his little sister was already sleeping.
He lied down next to her, smiling as she instantly came closer to him despite not even being awake. He held her tight, still unbelievably happy and enjoying her warmth, feeling completely at peace. It didn't take long for him to drift off.