"Wakey-wakey, Zuzu! You're leaking again!"

The fire prince slowly opened his eyes and the first thing he noticed was his sister smiling at him. The second thing he noticed was that the thick wad of cloth around his waist was soaked and indeed leaking onto the mattress of his crib.

"Well, get up! We better get you changed out of that yucky wet diaper, don't we?"

His sister's voice had a caring tone to it, but there was always something scary about it. Something threatening. Every request said in a sickly sweet, motherly tone also sounded as if there was an implied "...or else."

"Y-yes, Azula..."

Azula cleared her throat at glared at him.

"What was that?"

Zuko flinched and quickly corrected himself.

"I-I mean yes...big sister."

Azula's demeanor quickly changed back to the caring tone from before.

"Good boy."

She helped him out of his oversized crib. Of course, she wasn't really his big sister. He was the older one, but he has always been more timid and submissive, while she had a commanding presence and was very mature for her age. So, with their mother gone, and their father busy with the war and politics in general, Azula took it on herself to care for him. And with his timid nature and his bedwetting, the "big sister" decided she should treat her "little brother" like the baby he – according to her – actually was.

"There, up you go. Time for changies!"

She helped him up onto his changing table and gathered the supplies. These diaper changes every morning had become a daily ritual, but that didn't make them any less humiliating.

"You've really been wetting a lot lately," Azula said as she opened up the diaper that was visibly drenched in the older boy's pee and reached for a washcloth in a bowl of water, "We have to do something about that."

Zuko flinched at the ice cold wet cloth that his sister used to clean up his private parts. Again, even though this was something she did multiple times a day, he still didn't feel comfortable with his sister touching his genitals in this way. Also, what did she mean when she said she had to do something about his wetting?

"There, all clean. Now for your fresh diapie..."

Zuko's eyes widened as he saw his sister grab three cloth diapers.

"Wait, what?"

"I just told you: We need to do something about your heavy wetting, so we need to add some layers to your diaper!"

He couldn't believe this! He could barely put his legs together when wearing one of these diapers, but three? Would his pants even be able to hide them?

"I...I...No!"

His sister glared at him and he froze as he realized what he just did.

"What was that, little brother?"

He was about to back off, but then managed to gather what little courage he had to put his foot down. Enough was enough!

"I've been playing your stupid game long enough! This is going too far!"

He got up from the changing table, but as he was about to walk to his closet, he felt a stinging in his back, and fell to the floor, unable to move. As he looked up, his sister looked down towards him, with a sadistic glare in her eyes.

"Like that trick? Learned it from Ty Lee. It's perfect to punish little baby brothers who don't know their place."

She pulled over a chair and lifted her brother up, putting her over her lap, and started spanking him viciously.

"Such a bad baby!"

The smacks stung Zuko's behind. He figured she was charging them with some of her bending.

"Bad, bad baby!"

Three more smacks landed on his bare bottom and he started crying.

"You better say you're sorry!"

She kept smacking as Zuko sobbed an apology.

"I-I'm s-sorry..."

"I'm sorry, what?"

Azula accentuated her last word with an especially hard and electrically charged SMACK.

"I-I'm sorry, b-big sister..."

The princess smiled triumphantly, but that was not yet enough for her.

SMACK!

"What are you?"

"I-I'm just a baby..."

SMACK!

"And?"

"...a-and I'm gonna do what big sister says..."

SMACK!

"Like?"

"...l-like wearing my three diapers..."

With one last SMACK, Azula put her baby brother back on the changing table and put the three diapers on him, sure that, even if he could move, he would be too intimidated to run away.

"Oh, and by the way, Zuzu...I just decided that for that tantrum just now, I'll be completely revoking your potty privileges for today."

Sniffling, Zuko asked:

"A-all of them?"

Azula smirked darkly.

"Yes. All of them. Even if you notice that you need to go pee pee – and let's be honest, you wouldn't anyway – you'll have to use your diaper. And the same goes for your little stinkies."

She pinched his cheek, which coincidentally was reddening at the same time. It's not like using the "potty" was much more dignified than using his diapers, since Azula still insisted on her brother telling her when he needs to go, and her coming with him, watch him do his business, and wipe him clean afterwards, usually while making some humiliating comment. But still, doing his "little stinkies" in his diapers was way worse than that. But with his butt still burning, he knew better than to protest.

"There, now let's get you dressed."

Azula led Zuko to his wardrobe, where she picked out a plain shirt and pair of pants for him and proceeded to dress him. Luckily, the clothes were still able to cover the diaper. Not so luckily, There was still a noticeable bulge visible under Zuko's pants.

"Okay, Baby Zuzu, now it's time for your num-nums!"

Zuko rolled his eyes as his sister took him by the hand and led him into the kitchen, where his highchair was already waiting for him. Azula had it made especially for her baby brother. She put him down in his chair, put his bib on him, and began heating a bottle of milk using her bending.

"Here we go! Now be a good little baby boy and drink it all up for big sister, hm?"

Again, his sister's sweet tone had the creepy hint that even the slightest misdemeanor would result in another trip over her lap. Or maybe even something worse. So Zuko didn't even attempt to struggle when Azula put his bottle into his mouth, and suckled on it quietly, while she prepared his oatmeal.

"All done with your milky? Then here come your yum yums! Open wide, baby brother!"

Again, Zuko, despite feeling incredibly humiliated, knew better than to protest and opened his mouth while Azula shoveled spoonful after spoonful of oatmeal into his mouth, way too fast for him to properly swallow in-between portions. He figured she was doing this on purpose, since this resulted in spit and mushy oatmeal dripping from his mouth directly onto his bib, making him look even more babyish than he already was.

"Oh my, my little brother is quite the messy eater, isn't he?"

She giggled, while a sadistic grin made its way onto her lips. She was enjoying this, that much was clear to Zuko. He was at the mercy of someone who enjoyed nothing more than to humiliate and belittle him, and had been for years now. He resented that, and he resented that he was unable to fight back. Every time he tried, she managed to get him back under control, and even their father seemed to be on Azula's side.

"There, all done! My, this will probably lead to a very full diaper later today, won't it?"

She giggled again, and Zuko hated the reminder that he was forced to do more than just wet himself today.

"But anyway, I have some errands to run and I just can't leave you alone here. So come, let's go on a little walk, Zuzu..."

As far as Zuko knew, nobody in the kingdom was aware of the fact that their prince was still wearing and using diapers like a two year old infant. So far, his diapers have always been just slim enough that they weren't visible underneath his wide pants. However, today, he was wearing two extra diapers, and they showed their bulk. Zuko was hoping that they weren't that obvious after all, and that he was just worrying about nothing. But as he was trailing behind his sister, who held his hand in hers, as if she was taking care of a toddler, he still couldn't help but feel like all eyes were on them. Though that might just have been because they were royalty.

They entered a store and Azula started talking to the man behind the counter. Zuko wasn't listening to what they were saying, as his attention was drawn to a couple of "WANTED" posters on the wall.

To his surprise, the four posters he saw all showed children, who were apparently wanted for treason against the Fire Lord himself. Two of them, a boy and a girl wearing traditional Water Tribe clothing, seemed to be around his age. Another one, a small girl in Earth Kingdom garb, seemed even younger. And the last one, the one with the highest bounty set on him, a boy with a bald head and an arrow tattooed on it, also seemed like he was barely older than twelve years old, at most.

As he looked at the posters, Zuko of course felt a sort of anger towards them. They were criminals, and on top of that were apparently working directly against his father. But despite both his family and his national pride resulting in a calm anger, there was also another feeling. A fascination, if not jealousy. There were these kids, apparently doing enough with their lives to make a name for themselves, to incite the wrath of the most powerful man in the world, and they were even younger than him! Yes, they were criminals, they were evil, they were going against everything his family and his nation worked so hard to build for themselves...but still. The mere thought that kids even younger than him were doing such things out in the world, while he was being mocked, humiliated and being treated like a literal baby, it made him so jealous...and also a little sad.

"Come along, Zuzu!"

He was ripped out of his thoughts by Azula pulling him out of the store on his arm. They had barely been out on the street before Zuko heard a voice behind him.

"E-excuse me..."

As the royal siblings turned around, they saw three girls around their age standing there, looking a little flustered, if not starstruck.

"A-are you the real princess Azula and prince Zuko?"

As usual, Zuko's sister took it upon her to speak for the both of them. In her usual, somewhat dismissive tone.

"Yes. We are."

"Oh my goodness!"

The three girls were now beaming and blushing, visibly excited to meet royalty. Zuko also got a little excited. Besides his sister, he barely had any contact to people his own age, much less to girls. And the young prince couldn't help but blush a little at the three beautiful young ladies paying so much positive attention to him.

Without Zuko noticing, Azula smirked. She then put her arms around Zuko, one on his diapered behind, the other one on his stomach. In a much friendlier tone, she said:

"Yes, I'm princess Azula, and this is my brother, Zuko. Say hi to these nice girls, Zuzu!"

Before Zuko could stammer a shy welcome, he suddenly felt his bowels move and made a face. His sister leaned in and whispered into his ear:

"What's wrong, brother? Do you need to potty?"

Zuko only nodded in response. Azula smiled.

"You know the rules..."

Somehow, he couldn't help it. Before he even knew what was happening, the three girls in front of him wrinkled their noses as the air was filled with the smell of Zuko's very dirty diaper.

"Oh no!" Azula exclaimed loudly, while giving her brother's diaper a pat "Looks like the little prince made a royal boom boom in his diaper!"

The girls looked confused at first, but their confusion quickly dissipated as Azula began to lie her brother down on a nearby bench and remove his pants, making his diapers visible not only to the three girls (who now erupted into laughter), but to all the people on the street, who now stood by to watch the spectacle. The mere fact of his childish underwear being on display like this was bad enough for Zuko, but knowing what would come next brought him close to tears. Azula leaned in, looking to the outsiders as if she was kissing her brother to calm him down, but in reality, she whispered to him:

"This is going to be so embarrassing for you...but I'm going to enjoy every second of it, baby boy..."

With Zuko sobbing, Azula opened up his used diaper.

"Pew! What a big stinky you made in your diaper, baby Zuzu!"

The crowd was laughing as Azula wet the washcloth and started cleaning up Zuko's diaper area. After putting his used diaper in a special bag, she put another three diapers on her brother.

"And you know what? I don't think we're going to need these anymore..."

With that, she threw away Zuko's pants and helped him up. With his diapers on full display, he followed his sister, who was leading him back to the palace, while all the onlookers laughed on his behalf.

Zuko was lying in his crib, since it was time for his nap. But before he could slip away into the land of sleep, to hopefully escape the terrible events of this morning, Azula entered the room. Her expression was cold, as was her voice.

"I saw the way you looked at those girls."

Zuko just swallowed, too scared to say anything in response.

"You've been difficult recently. Your tantrum this morning was the third one this week. And now you're looking at girls? In that way? Tsk, tsk..."

She positioned herself next to the crib, so she was directly looking down at him.

"I think I have to make this clear again: You are a baby! My baby! My plaything! I can – and will – do whatever I want with you. You never were anything more than a baby, and you never, ever will be. You depend on me! For everything! To feed you, to bathe you, to dress you...even to go potty! But you know, that's what I really wanted to talk to you about..."

Zuko flinched as she bent down, lightly stroking his stomach.

"...since you don't seem to know your place, I decided to revoke your potty privileges. Forever!"

Zuko's eyes widened as Azula laughed and continued to pet his belly.

"Yes, little Zuzu. You're a baby. And it's silly to let babies use the potty. So, to teach you your place, and your dependence on me, it's only diapers for you from now on. Diapers for the rest of your life. So you hopefully start to appreciate your big sister changing you. Oh, and to teach you this lesson right away, here's another trick I learned from Ty Lee..."

She put her hand flat on his stomach, and after a few seconds, his stomach started aching and his bowels emptied themselves into his diaper.

Azula smiled darkly, and got up to leave the room.

"Enjoy your nap in your smelly diaper. It won't be the last. By far."