Some things never change, even after a thousand years.

It had been a couple of months since Princess Celestia sent Twilight Sparkle to Ponyville to oversee preparations for the Summer Sun Celebration. Of course, Celestia had much better foresight and planning than she had let on. She knew that Nightmare Moon would be returning that night, and that the Elements of Harmony were the only things that could help. Twilight had the necessary skills to be an Element, but she needed friends that embodied the other personalities. That was the only doubt Celestia had in her pupil.

Thankfully for Equestria, Twilight pulled through. Through means beyond her control, she found five other ponies that would stand by her, earned their Elements, and released Princess Luna from the clutches of her darker side. For that, Celestia could never thank these six mares enough.

And Luna, she was welcomed back with celebration and praise. It was a shock to the princess of the night, because the last thing she remembered was ponies ignoring her. Seeing everypony being so kind and welcoming really hammered in the guilt of what she had done as Nightmare Moon. Luna was lucky to have a caring older sister to help her through.

While she was working on it as well as she could, Celestia was amazed by the enigma of Luna's psyche. Any licensed professional would be lost. The only reason Celestia was making progress was because Luna was willing to talk to her. Even ignoring Luna's shyness, enhanced exponentially by a thousand years away, but she had some things that she couldn't share with anypony other than the one she trusted most.

Celestia and Luna were opposites as their daily rules would suggest, but that foil also meant they could be identical. Both were caring to the subjects that appreciated them, both were playful given the chance, and both were closet perverts. It wasn't a coincidence or sisterly bond, it was just the sort of thing that developed in the positions they were in.

When you're a princess, it's very important to keep anything you don't want everypony talking about heavily out of sight. This meant that, against her wishes, Celestia grew up repressing her sexualities. Doing that sort of thing causes those feelings to manifest in other ways. She started having stranger fantasies during her private times, to the point where she was scared and confused about what she was doing. After all, this wasn't something she could admit to by looking for an answer.

Through means of “research” that she wasn't proud of, she had discovered that she was perfectly fine, just a mare with an assortment of kinks. After all, she was enjoying it, and nopony else had to know. Over time, she grew used to her fetishes and learned to accept them, until the idea that it was weird no longer crossed her mind.

It was brought back to the forefront of her thoughts a few years later, when Luna ran into her room crying. She had been reaching the age of sexual experimentation, she had been raised with the same restrictions as her older sister, and she was always the more sensitive one. This discovery and reaction was inevitable. Luna tearfully confessed what she had done, and begged her older sister for advice.

Like any good older sister, Celestia held her younger sister close and reassured her that things were fine. To back up her assurances, she explained how she had gone through the same thing at her age, and told Luna what she had done before. She probably went into a little more detail than she should have, but Luna didn't object and seemed to grow more comfortable, just hearing her older sister confess to the same thing she was upset about.

Celestia finished and they hugged it out, and since then, they were extremely open with each other. They could hold casual conversations about sexual matters, talk about their partners of the previous night, and engage in friendly competitions. It would be criteria like which one could get a stallion faster, or which one could find a stallion that would tolerate their strangest fetishes, all while disguised as normal mares.

On the occasion they wouldn't be able to leave the castle, they would usually resort to battles of attrition, such as longest time without clopping, which was quickly abandoned when they decided it was a lose/lose fight. Actually, every one-on-one competition would end like that. Who could endure whipping, binding, it tended to end poorly and be difficult to hide.

But now that she was back, Luna wasn't going to let her sister get the better of her. Tomorrow would be the first day she would return to hold court, now that she had made excellent speech progress. She was working past her antiquated dialect, with a gentler tone. With this milestone approaching, she felt it would be the best time to bring back the ongoing war. “Do you think I'll do well tomorrow, Tia?”

Celestia gently hugged her younger sister. “I know you're nervous Lulu, but I promise, the ponies will love you. You'll do just great, just like you always have.”

Luna sinisterly grinned at her sister. “Oh, I don't think I'm nervous enough yet. What say we make this a game?”

Celestia caught on to Luna's suggestion, and decided to play along. “It's been a long time since we've done anything like that. What do you have in mind?”

Luna stroked her chin, and slyly responded, “I'm pretty sure we haven't done this one before, so perhaps a urine holding contest?”

Celestia considered the idea. Compared to their other physical challenges, this was simple, easy to hide, and sounded pleasurable. Also, it's a pretty low risk for alicorns to undertake. A normal bladder could hold an impressive amount of pee if pushed to their limits, but it was nothing compared to an alicorn, who could hold upwards of a gallon without worry. She nodded. “Alright Luna, you're on. But know that you're facing a force to be reckoned with here. I've spent all this time placing royal duties before myself, and that's trained me quite well.”

Luna scoffed. “Please, being imprisoned inside the moon didn't keep me in my physical state, so I technically didn't get a leak that entire time. If we're really doing this for tomorrow, we need to drink a whole lot tonight.”

Morning came sooner than expected, possibly due to Celestia's eagerness to show her sister up. Or maybe it just felt that way because it was messing with the normally nocturnal Luna's sleep schedule. Either way, Luna was groggy, and she was going to make it known.

As the sun was rising, Luna was changing out of her casual clothes into the formal attire she would need to wear, when there was a knock on the door. Not willing to put up with shit, Luna angrily called back, “I'm barely dressed in here, go away!”

Despite the shout, the door opened anyway, and on the other side was Celestia, already in her yellow dress for the day, holding a mug in her hand. “Come on, Luna, we've got work to do. You want some coffee to wake yourself up, or are you afraid of having any more liquids?”

Luna wasn't going to deny to herself that her bladder was already sending her signals, but she wouldn't give her sister the satisfaction. She determinedly grabbed the mug from Celestia's hand and chugged the hot drink down in one gulp. Plus, it would help her wake up quickly, allowing her to focus on the ponies she'd be talking to, which would in turn keep her mind off the need that was sure to be a big problem later on.

Once the cup was empty, Luna slammed it onto her table and sighed satisfyingly. “You'll have to try better than that to beat me, Tia. I can drink 17 cups of coffee in a morning.”

Celestia laughed. “I don't think so, last time you tried that as a filly, you got so hyped up on caffeine that you claimed you had 'returned from Tartarus to do battle' with everyone you met.”

Luna blushed and looked away. “Oh. I didn't think you would have remembered that.”

“How could I forget? You also wore a mask, a bright glowing red one. You wore it in my room while I was trying to sleep, and I almost wet my bed in fear when I saw it. So are you going to put on clothes, or would you rather just stay here in your underwear? Actually, I already know the answer to that.” Celestia opened Luna's closet and pulled out a purple dress. “Put this on now.”

Luna sighed. Even without their challenge, today was going to be agonizing.

The day went on, with Celestia and Luna at the helm of Canterlot Day Court. Ponies would come in to request things of the princesses, either funds, workers, or the service of the Royal Guard. A lot of these requests were absolutely ridiculous, like the one in front of them, asking for a large sum of ponies to do work, assuming that more ponies meant faster work.

Through centuries of experience, the Royal Sisters had learned how to expertly talk with each other during sessions like this without being noticed, through a mix of whispering at the right times, and a harmless perception filter. Celestia was making use of it right then. “Can you believe this? He thinks having a large group of ponies all working on one goal is going to end in success, instead of everypony overstepping each other's work.”

“There's some precedence to this. It took 16 days of continuous work, but 90,000 ponies completed an adventure, and even created a religion in the process, praise Helix.” Luna moved her hoof across her body in a specific fashion, culminating in a swirl pattern.

Celestia rolled her eyes. “I have no idea what you're referring to, but there's no way that sort of thing could ever be replicated.”

“They did it again, beating their old team in the process, and are underway on a third expedition. Are you going to answer him or not, I'd like to finish this as quickly as possible.”

Celestia smiled at her younger sister. “Getting a little anxious, are we? Perhaps you'd like to take a certain break now?”

Luna couldn't deny that she was feeling a very strong growing pressure down below, and she was thankful for the long dress, giving her enough privacy to tightly cross her legs. Things were not looking all that great for her, but she was determined not to be obvious about it. “It hasn't even crossed my mind, sister. You know as well as I that this is painfully boring, and I just want to get back to my life and sleep.”

It was a reasonable explanation, but Celestia wasn't going to buy it, she knew Luna must have to pee badly by now. She was also skilled in keeping it hidden, but Celestia was desperately wishing for a bathroom visit. She, too, was crossing her legs under her dress. She wasn't going to show weakness to her sister or her subjects, but she was seriously doubting her ability to keep this up. After all, if she couldn't hold it any longer, she'd have to either openly hold herself or have an accident.

Luna was having the same worries next to her. It was going to be painful for both of them.

The hours dragged on, and things were looking grim for the princesses. Both of them were using everything in their power to keep composure, and both were almost spent. If the day went on any longer, there would be no hope for them.

Because of this, they were both thankful to the high heavens when Captain Armor stepped before them and declared, “The Day Court of the Royal Pony Sisters is now closed for the day, I would like to ask all of you to please leave the premises, and return on another day.”

The ponies in the line grumbled, and the other guards guided them out. It took a few minutes for the room to clear, and during that time, Celestia and Luna had to stay in their spots and still look dignified. Both were now dying to pee, and were begging for the day to end so they could at least grab themselves to buy more time.

At last, the last of the crowd went out the door, and Celestia moved her hands towards her crotch for a squeeze, until she noticed Shining Armor was still in the room. He turned to them and began explaining. “Sorry I ended things a little early, princess, but I've got plans for tonight that I really can't miss.” He patted his coat's pocket and smiled, indicating something important inside, perhaps a small box.

Despite her romantic side, Celestia normally wouldn't approve of ending court early just so her Captain of the Guard could go on a date, but every minute was of the essence now, so she would take what she could get and make her way to the nearest bathroom as quickly as she could manage. She thanked her Captain, but he didn't respond, his focus instead drawn to Luna.

Celestia turned her attention to her younger sister, who was tightly grabbing herself, either unaware or not caring if anyone else was in the room. Looking at her sister giving into her urges was not helping Celestia's situation in the slightest. Thankfully, Shining Armor didn't seem to care. He just held his hand up and started walking away. “Alright, I'll see you two tomorrow, then.”

Now that they were alone, Celestia was going to join her sister in at least partially giving into her body's demands. Even with pressure on her privates, the knowledge that relief was not that far away caused her to dribble a little into her pink panties. Wordlessly, the two princesses started running out, before they were reminded why that was a bad idea. The sudden spasms from both their bladders forced them to bend over to contain themselves. It worked for the time being, but now it would require everything they could manage to make it to safety.

Their personal bathrooms were, without a doubt, too far away to conceivably make it, so their only option were to find the closest possible choice, and their frantic state of mind wasn't allowing them to find it mentally. So, all they could do was aimlessly wander through the castle halls and hope they stumbled across a toilet before time ran out.

Luna was not very fond of waiting. “Ooh, I don't know how much longer I can wait, Tia! I need to go potty now!”

Celestia was trying to be sympathetic, but that would be hard to do when they were in the same situation. “I know, Luna. Just try to hold on a little bit longer.”

They passed multiple guards and castle staff in their struggle, attracting attention, but neither of the two could care in the situation they were in. All that mattered to them was making it to any bathroom. At this point, even a normal bathroom was seeming like a luxury, dignity be damned, they might take anything at this point.

It didn't come to that, though. Their arduous walk paid off, and they were rewarded with a small bathroom. As in, only one toilet, no stalls. This would prove to be a difficult problem, considering that two was a greater number than one. Good thing that Celestia was a kind and caring older sister who would give up her well-being for her younger sister's sake.

Or she would be, if she wasn't about to burst, a thought completely consuming her actions. Being slightly ahead of Luna already, she made it into the bathroom first, and shut the door behind her. When Luna realized what had happened, her eyes grew wide, and she threw herself against the door, pounding on it with her free hand. “What are you doing, Tia?!”

“I'm sorry Luna, but I need this just as much as you do!”

Luna tried the doorknob, but it was locked, as it should be. “Please, just let me in anyway! I'll use the sink if I have to!” She was being serious, anything that could offer her relief sounded great right now.

No reply from the other side, which was making Luna's situation seem even more helpless. She continued knocking, even though she knew it was pointless now. Droplets in her black panties were picking up into a light stream, running down her legs onto the marble floor beneath her.

Celestia felt a pang of regret for what she was doing, but it wasn't enough to overwhelm her biological needs. She quickly pulled the fabric of her dress up as high as she could, held it up with one hand, and used the other to pull down her slightly more than damp panties to her ankles, before finally putting her butt on the seat.

Outside the room, all Luna could hear was a loud, relieved sigh and the distinctive sound of a very strong stream of pee pouring into the toilet bowl. That was all it took for the ocean contained inside Luna to break free, absolutely ruining her panties in a matter of seconds, and not sparing much for the front of her dress that was still being pressed against her marehood. Suddenly, the fight was lost, there was nothing Luna could do at this point. One of the princesses of Equestria, a vitally important pony to the flow of day and night, dreamwalker that helped ponies with their problems, was peeing herself in the hallway of the castle.

For 10 minutes, that's all that happened. Celestia sat on the toilet and peed exactly as one would expect, though with more relieved sighing and a harder than necessary stream, while Luna did the same thing in the hallway. Though it would be natural for her to drop to her knees, she at least had enough control to know that doing that would do more damage to her clothing. She had also since let go of her dress to prevent the already big wet spot from growing even worse. In all respects, it was the most calm and dignified wetting that could be reasonably expected, only tainted by the tears running down her face.

Finally, Luna's stream ended, leaving one gigantic puddle clearly visible on the floor. Just as Luna sighed relief that it was over, a flush came from inside the bathroom, followed by another quick stream of water from the sink. Once that shut off, the door opened, and Celestia stood on the other side. She scanned the sight of her younger sister, the yellow-tinged puddle grabbing her attention. “Listen, Luna...I'm really sorry. I know that just locking you out wasn't the nicest thing to do, but you understand the predicament I was in.”

Luna was definitely still upset at what had just happened, but she still found reason to smile. “You know, Tia...I won the competition. I didn't lose control until I heard your splashing. It wasn't much of a victory, especially considering where I was standing at the time, but take the victories where you can, right?”

Celestia was pulled in by Luna's optimism. “Alright, Lulu, sounds like you did win. Congratulations, I didn't think you could beat me. You really have grown quite a bit, able to compete with your big sister like that.”

Luna batted her hand. “Come on, I don't think this is a good representation of by maturity.”

“You're right. But you still proved yourself here. You went through a bad situation, one that could reduce any pony to a complete mess, and you still managed to handle it with grace and an eventual smile. That takes a lot of bravery and strength.”

Luna could only smile and blush at her sister. “It's not that hard to deal with a bad situation like this, because I know that I'll always have a sister who's proud of me.” She opened her arms for a hug, and Celestia stepped closer to join, not caring what was still all over the floor surrounding her sister, because some bad things are worth sticking through for your sister.

Because some things never change, even after a thousand years.

Author's Note

Downplayed fetish for cute. This is the second draft of the chapter, and I still can't escape the cuteness proximity. Yeah, Luna's hot, sure, but she's also adorable. I like girls like that.

Next chapter, in response to the Jananimations C&D, Button's Mom. Maybe, I don't feel like making a promise.