"Help!" A young filly shouted as she struggled to keep her head above water. "Somepony help me!"
"Fear not, young filly!" Came a heroic cry from nearby, a massive pirate ship appearing out of thin air and floating next to the waterlogged filly. Standing at the helm was a midnight blue alicorn with a mane willed with twinkling stars, sporting a fashionable pirate hat on her head, a red feather stuck into the brim. "I am here to save you from this most dire of nightmares!"
"Princess Luna!" The filly cried out, paddling closer to the ship as a life preserver was thrown into the water from the deck. Quickly grabbing onto the inflatable ring, she was quickly hauled up and onto the deck, plopping onto the ship in a wet heap. "You saved me!"
"But of course," Princess Luna said as she strolled across the deck. "Tis my duty to ensure your dreams remain free of fear and—" Luna was cut off as the filly latched onto her leg, muttering, "Thank you!" over and over again, bringing a smile to Luna's face. Despite being a thankless job, Luna had recently taken up her former duty as a guardian of dreams, working hard to protect ponies young and old from the terrors that plagued them during the night. And, despite knowing that this filly would likely forget about this moment upon waking up, seeing them so happy is what made it all worth it.
"Sleep well, my little pony." Separating herself from the dream with but a thought, Luna found herself once more standing in the Dream Realm, an amorphic realm filled with countless orbs of light bearing into the dreams of her sleeping subjects, each one showing one pleasant dream after another with nary a nightmare in sight.
"It appears that my duties are at an end this night," Luna muttered to herself, a habit she had picked back up along with her title as the "Guardian of dreams." "Won't be long until Tia awakens to raise the sun, so I should awaken as well." As Luna lit her horn to return to the waking world, she muttered, "Hopefully there will not be an unwelcome surprise awaiting my return…" before the Dream Realm disappeared in a bright flash of light.
Seconds later, Luna's eyes fluttered open as she awoke from her trance. She was then immediately assaulted by the overpowering stench of fresh urine, her nose wrinkling as she glanced down at the noticeable wet spot upon her lavender sheets. "Not again!"
Since returning to her duties overseeing the Dream Realm, Luna had begun to develop an embarrassing habit of wetting the bed almost every night, the side-effect of interfering with the dream of a pony who unfortunately still wet the bed themselves. Luna had tried to find a solution to this growing problem, but so far her efforts had yielded nothing but multiple loads of wet sheets for the castle maids to wash. "In my day, young fillies and colts were trained before they learned to walk!" Luna grumbled.
Worse still, Luna had started hearing whispering of her "little problem" among the castle staff, making her cheeks burn with embarrassment. "I must find a solution to this irritating problem at once!" Rolling up her wet sheets with her magic into a ball, she tossed them into the laundry bin before sauntering off to her personal bathroom to prepare herself for the day. "A nice shower will help me feel better…"
One shower later, and Luna was indeed feeling much better, trying her best to put that morning's events out of her mind. However, as she worked to dry her hair, her ears perked up at the sound of knocking against her bathroom door. "Begone, I will be out once I am ready!"
"Luna?" Came Celestia's voice from the other side of the door. "It's me. We need to talk."
"Tia?" Wrapping her mane in a towel, Luna walked over and opened the door to find Celestia standing before her, a stern frown on her lips. "Is something wrong?"
"I was about to ask you that very same question," Celestia replied, a concerned look in her eyes as she asked, "Did you sleep well? No troubles or issues while watching over the Dream Realm that I should know about?"
"No, sister, I slept fine," Luna said with a huff. Tia just can't help but be a mother hen sometimes. "Now, if there is nothing else, I am in the middle of—"
Luna's attempts to close the door where halted as Celestia placed her hoof in-between the door and frame. "Don't lie to me, Luna."
"Tia, cease this at once!" Luna yelled as she tried to force the door shut. "I am not in the mood for games!"
"Neither am I." Throwing the door open with her magic, Celestia levitated over the bundle of wet sheets for Luna to see. "Would you care to explain these?"
"I… I…" Luna stuttered, unable to formulate an acceptable response as her shame was held for all to see.
Sighing, Celestia floated the wet sheets back into the laundry bin before stepping closer to her sister and pulling her into a hug. "I'm sorry, Luna. I don't mean to embarrass you, but I've been hearing rumors amongst the castle staff about your little… "problem"."
Luna buried her face Celestia's fur. "So, now you know. Some princess I am…"
"It's not your fault, Luna. Truth be told, I encountered the same problem while managing your duties during your absence and managed to figure out a solution."
"You did?" Luna asked, looking up at Celestia hopefully. "Then you must tell me how you resolved it at once!"
Celestia became strangely silent, looking away as a mitigable blush tinted her cheeks as well. "It… it might be better if I showed you. But not now."
"But—" Before Luna could argue, Celestia silenced her by placing a hoof to her mouth.
"I'll show you tonight, I promise."
Luna pouted, looking like she still wanted to argue, but trusted her sister's judgment. "Alright. Tonight then."
{Later that night…}
"Luna, please come out."
Night had fallen over Equestria some time ago, and Celestia found herself in the same spot she'd been that morning: standing in her sister's chambers outside her bathroom. As promised, Celestia had brought with her a solution to help Luna with her bedwetting and, like she had expected, Luna had not taken it well, shouting at her before locking herself in the bathroom.
"No," Luna grumbled through the door. "I am not a foal, sister, and I will not dress like one!"
"Please, Luna. I beg you to reconsider—"
"Neigh! Now be gone and leave us in peace, oh foul sister of mine!"
Celestia loudly sighed, turning away from the door. "Alright then…" She said, loud enough that Luna could clearly hear her through the door. "I guess I'll just have to warn the maids to prepare for an additional load of linens tomorrow…"
Celestia made it three steps towards the door before she heard the sound of the bathroom door creaking open and Luna stuttering, "W-wait…"
"Yes?" Celestia replied, glancing over her shoulder as Luna stuck her head out of the bathroom, blushing redder than a tomato.
Sighing in defeat, Luna muttered, "I… I'll wear it, okay? Just for tonight!"
Without a word, Celestia passed the item she had brought to Luna, who quickly snatched it into the bathroom and slammed the door shut again. Walking up to the door and placing her ear to it, Celestia could just make out the sounds of her sister fumbling around, grunting as she likely struggled to change herself. "Would you like some help, Lulu?"
"No! No, no, no! We are fully capable of… changing ourselves, thank you very much."
"Alright, if you're sure." Celestia waited outside the bathroom for Luna to finish, and it wasn't long before the door opened once more and Luna trotted out, her head hung like she was walking towards an execution and her face still blushing profusely. Not that she didn't have good reason to be embarrassed, given that wrapped tightly around her loins was a very large, and very thick diaper, the bulk easily pushing her legs apart and turning her walk into more of a waddle.
"… Are you satisfied, sister?" Luna grumbled, refusing to look Celestia in the eye.
"Oh, don't be like that, Luna. This is only until you get accustomed enough with the dream realm that you stop waking up in wet sheets. Besides, you may find that changing a wet… diaper… will be easier in than changing wet sheets every morning."
Luna winced at the word. Diaper, like those worn by foals, not Alicorn Princesses older than the average pony by centuries. "Be that as it may, I still don't like this. And why in Mother's name is it so thick?!" To demonstrate, Luna tried to close her legs, unable to as the huge bulk resisted her.
"Oh, that's partially due to the material. These days they're stuffed with clouds to make them more comfortable and also recyclable at the expense of being so thick. It also happens that that particular brand is for nighttime accidents and…" Celestia looked away, tittering slightly as she said, "… I thought you might like the designs on it."
Looking behind her at her massive behind, Luna noted that the leg gathers had designs of fluffy clouds around them, and a quick glance down reveal the waistband and front were covered in cute crescent moons. "I will admit I find the design… acceptable. At the very least it fits. However…" Grinning devilishly, Luna turned her attention towards her sister, the older princess beginning to sweat under Luna's glare. "The fact that you came up with this solutions tells me that you suffered the same fate while you oversaw the dream realm during my absence. Am I correct?'
This time it was Celestia's turn to blush as she hung her head and muttered, "… Yes…"
Luna snorted as she suppressed a laugh. "Now we are even more curious about what kind you wore, Sister."
"I… well I… Oh, would you look at the time!" Celestia said, visibly flustered as she almost stumbled over herself racing for the door. "I should really get to bed, lots of busy meetings and princess things to do tomorrow!" In a flash, Celestia bolted out of Luna's chambers, slamming the door behind her.
Now along, Luna frowned as she glanced once more at her humiliating state. Still, she could take solace in knocking that this matter would stay between her and Tia, as she knew her sister would never willingly reveal something that could damage either of their reputations as this. Sighing, Luna trotted over to her bed, the diaper she was wearing once again distorting her walk into more of a waddle as she lifted herself up and crawled into bed. As she lay on her back, staring up at the constellations drawn across her ceiling, she took a few moments to consider her new attire, noticing begrudgingly how softly it comfortably wrapped around her and how soft it was to the touch, poking it with her hoof.
"They're comfortable, at least…" Luna said before she lay her head back against her pillow, her horn glowing as she began to slip away to the Dream Realm.
Meanwhile, Celestia breathed a long sigh of relief when she finally reached her own chambers, having put as much distance as she could between her and Luna's room without alerting the guards on duty that something was amiss. Waving and smiling as a pair of night guards passed her by, Celestia quickly darted into her room and slammed the door shut, locking it behind her. Panting heavily and sweating profusely, Celestia breathed deeply as she tried to get her racing heart to calm down, her eyes drawn to her wardrobe on the other side of the room.
Luna must NEVER know. Truth be told, Celestia had never fully gotten over the bedwetting problem she had developed as a consequence of patrolling the Dream Realm in Luna's stead. Sure, it was far less frequent than it had been centuries ago, but it still happened from time to time, especially when she was really and truly stressed beyond her wits like she was right now. Trotting over to her wardrobe, Celestia threw the doors open and pushed aside a row of dresses, staring at the seemingly empty spot behind it. Lighting up her horn, Celestia dispelled the glamour keeping her secret hidden, revealing a half-empty package of diapers stashed at the back of her wardrobe.
Pulling one out, Celestia quickly diapered herself, a skill she had never thought she would have to learn. As she finished, she walked over to her mirror and turned around, smiling at the large image of her cutie mark on the back of the diaper. Waddling over to her bed, Celestia crawled beneath the covers, content in the soothing feeling of the padding wrapped around her as she drifted off to sleep.
The next morning, both sisters would awaken to the discovery of a thoroughly soaked diaper.
