Author's Note

Well, since the voters picked Princess Celestia, Princess Celestia it shall be. And since she's going to be diapered and babied alongside Twilight, that means somepony else has to be the caretaker. Guest caretakers can be allowed, as long as they are specified ahead of time.

As usual, it was Scootabom1, who proposed the idea of Princess Celestia being regressed physically, and using a spell to disguise herself and Twilight as actual foals, with Pinkie Pie as the caretaker.

In contrast to all previous characters voted upon, this is the only time I will allow Princess Celestia to be a playmate for Twilight for however long this fic remains active.

And even though physical regression and disguses are possible, I am still ruling out the usage of any school aged or younger characters as a playmate for Twilight. Since this fic does have a Sex tag (due to the original fic also having one), I don't want to get into any trouble for having underaged characters in situations that could be said to be "sexual" (Spike is allowed since his exact age is ambiguous).

Characters ineligable under any circumstances:
Starlight Glimmer
Discord
Trixie
Sunburst
Cutie Mark Crusaders
Flurry Heart
School aged or younger children (i.e. Cake Twins)
Characters introduced after Flurry Heart (Starswirl the Bearded, the Pillars, Star Tracker, Mudbriar, etc.)
Equestria Girls characters other than Sunset Shimmer/the Dazzlings
Princess Celestia

Characters that can only be done in group pairings:
Mane six
Princess Cadence
Princess Luna
Octavia and Vinyl Scratch
Twilight Velvet
Spitfire (with or without Wonderbolts)
Lightning Dust
Maud Pie (without Mudbriar)
Moondancer
Cheerilee
Lyra and Bon Bon (separately, or together)
Coco
Limestone Pie

Characters that can only be done in specific group pairings:
Spike (with mane six, Princess Cadence, or Sparkle family)
Shining Armor (with Princess Cadence, or Sparkle Family)

Characters previously voted on:
Prince Blueblood - One and a half votes
Derpy, Marble Pie - One vote
Sassy Saddles, Fleur, Princess Celestia - One half vote

Sunshine Smiles (Princess Celestia)

Twilight had closed her eyes and was concentrating deeply, listening to the rhythmic heartbeat of Princess Celestia as she was held close to the sun princess' chest. The padded alicorn was currently in the process of breastfeeding as part of a bedtime snack. She tried to time her suckling on Celestia's teets to the rhythm of the older alicorn's heart, a process easier said than done despite how many times she'd already done this.

Princess Celestia, for her part, just gently stroked Twilight's mane and rocked her former student back and forth while humming softly to her. "That's it, Twily," She encouraged in that gentle, warm, motherly tone of hers. "Just relax and drink up. Mommy's here for you no matter what," Then she winced a bit as she felt a sudden (albeit brief) burst of pain. "Ooh, careful, Twily! Not so hard!"

"Sorry, Mommy." Twilight sincerely apologized as she briefly removed her mouth from Celestia's nipples. Then she yawned as the warm, creamy milk worked its way down her throat and started to make her feel drowsy.

The sun princess simply used her magic to float her padded charge over to the bed, tucking her in and making sure her trusted companion Smarty Pants was close at hoof. Then she approached the bed and kissed her fellow alicorn softly on the forehead. "Sweet dreams, Twily. See you in the morning." And after turning off the lights, she departed the guest bedroom in which Twilight was staying, smiling all the while.

Yet as Celestia was making her way down the hall to her own bedroom, ready to call it a night after another day spent in the role of Twilight's "Mommy", the alicorn with a majestic white coat couldn't help but start pondering to herself. She was thinking once again of what her sister Luna had told her about Twilight's mental state as laid bare through the dream realm. True, Luna hadn't voiced any more concerns after that, and Twilight didn't seem to be negatively affected. But all throughout, the sun princess had occasionally noticed some troubling behavior. It was all just an act though, right? Twilight was merely "getting into character" as it were?

So why did Princess Celestia suddenly find herself worrying so much about her fellow alicorn's mental state and whether their frequent roleplaying as mommy and baby was really for the best? Both were getting what they wanted out of it, were they not?

These concerns had cropped up before from time to time, but this time they seemed especially prominent and concerning for the sun princess. Thus, she sat at the edge of her bed upon reaching her private bedroom and began to think. How could she alleviate these worries? How could she convince herself that everything was fine and that she was worrying too much about nothing? She thought briefly about discussing this with Luna, but decided against it. If Luna hadn't noticed anything troubling since her initial comment a long while back, talking with her would be pointless.

"Think, Celestia, think," Celestia thought to herself as she rose from her bed and paced back and forth for a while, deep in thought. "How can I truly see for myself if Twilight is okay? How can I make sure she isn't becoming too attached to me?" Minutes ticked by as she pondered and contemplated, trying to think of the answer that seemed just out of reach. Then, suddenly, it dawned on her! The answer was so obvious!

And with her mind made up, Princess Celestia opted not to go to sleep just yet. She had to make some arrangements if her recent epiphany was to be put into action. Yet she knew that she wouldn't be able to fall asleep until she was certain everything would be worked out. That meant there were certain ponies she needed to speak with before the sun rose in the morning.

Next morning, when Twilight yawned and wiped the sleep from her eyes, she initially had no reason to believe anything was at all different. "Good morning, Smarty Pants." She greeted her old foalhood doll as she used her magic to levitate said doll up close to her.

"Good morning to you, Twily," Smarty Pants replied. "Did you sleep good last night?"

The padded princess firmly nodded and happily stated. "Yes I did! And now I'm ready for another day of fun with my mommy!"

"Well I'm happy to hear that, Twily, because I'm ready for an extra special day of fun with you!" The familiar voice of Princess Celestia greeted from somewhere nearby. Yet strangely enough, there was no sign of the tall, slender alicorn with a majestic white coat. That seemed most odd.

"Where are you, Mommy?" Twilight questioned as she sat up fully in her bed. Now she had her first real sense that something was off: Everything around her seemed a lot bigger than she remembered it being from the night before! The size change startled her, causing her to gasp! "Mommy, what's going on?! Why does everything look so much bigger now?! Why can't I find you?!"

Celestia snickered, before the alicorn appeared right next to Twilight. "Because, Twily, it's all part of my surprise. I hope you like it." And once she was beside Twilight, it was possible to notice two things about the sun princess: The first was that she was now wearing a thick, white diaper in much the same fashion as Twilight. And the second was that she now appeared to be almost the exact same height as her fellow princess.

Blinking slowly as the realization dawned on her, the padded alicorn let out a gasp! "Mommy, you turned us into actual foals?!"

The regressed sun princess nodded, smiling brightly as she did so. "Yes I did. I figured I could use a bit of a break. And having seen how much fun you've had with your other playmates, I figured 'Why can't I join the fun too?'"

"Why turn us into actual foals, though?" Twilight nervously asked. "Everything looks so much bigger now. I would've been happy to have you in diapers as you were, Mommy."

Princess Celestia blushed a bit, her cheeks turning a faint shade of pink. "I guess I thought it would kill the immersion if you were looking up at me even if I was in diapers. Sorry, it was kind of a spur of the moment decision on my part. It sounded like a good idea, though," Turning to her fellow alicorn, she questioned. "You're not mad with me because of that, are you, Twily? If you are, I can turn us back to normal right now."

Yet Twilight immediately shook her head and protested. "You always know what's best, Mommy. I'm just a little bit..." Hesitantly, she added. "Surprised by all of this, that's all. If you really think this is the best way to spend time with me, I'll go along with it," She chuckled. "I guess that means now you're more of a big sister to me, like with my other mommy."

Still blushing a bit, Celestia gave off a nervous laugh. "...Yes... I... suppose I am. Not being the mommy is going to take a lot of getting used to. That's why I'm hoping you can teach me how to be the best foal I can be on my day off!"

Smarty Pants, meanwhile, saw fit to ask. "So, if you're not going to be Twily's mommy today, who's going to take care of us? And who's going to be doing all the grown-up things you usually do Mo... I mean big sis?"

The regressed sun princess regained her earlier cheerful persona as she answered. "Well, I made sure to clear everything with the castle staff and with Luna. They all agreed that Luna can manage my usual responsibilities for today, in exchange for me helping her with her duties at night. And as for who I got to look after us and make sure all our needs are taken care of..." She turned towards the bedroom door. "That pony should be arriving just about... now!"

As if on cue, the bedroom door swung open in dramatic fashion! And who should come literally bouncing in but Pinkie Pie herself in all her party pony glory?! "Tada!" She cheered as confetti burst out from between her hooves! "Here I am at last: Pinkie Responsibility Pie, the best foalsitter there ever was! Just ask Pound and Pumpkin Cake."

"Pinkie?!" Twilight gasped in surprise as she saw how much bigger the pink party pony seemed to be now! "Mo... er big sis asked you to be the caretaker?!"

Pinkie happily nodded. "Yes indeedy, little Twily," She kneeled down and eyed the regressed alicorn, then cooed. "Oh, and aren't you just the cutest little thing ever?! I could just eat you up, you're so cute!" And she proceeded to tickle Twilight, then blow a raspberry on her chest, causing the alicorn to explode with laughter.

Princess Celestia then cleared her throat. "Thank you for agreeing to this, Pinkie Pie. I know you've been busy since the Cakes left you in charge of Sugarcube Corner. You haven't even had much time to foal around. I'm sure you would've rather liked to have been the foal instead of the foalsitter."

The pink party pony waved a hoof. "Hey, you needed a foalsitter, and I needed a chance to refresh my foalsitter skills. Besides, how could I say no when you clearly wanted a break? Even mommies and daddies need a break from time to time."

"Well, if there's ever anything I can do to pay you back for this, you just let me know." The regressed sun princess sincerely stated.

Pinkie Pie giggled and snorted. "Why would I want anything else? Running Sugarcube Corner may not be all fun and games, but I wouldn't trade the smiles on the happy faces of my customers for anything in the wide world of Equestria. Besides, I still find time to do the things I like to do. And it's not like it's a permanent change, Mr. and Mrs. Cake are just on vacation right now. They'll come back eventually, refreshed and renewed," She then reached up a hoof and started digging into her mane. "Now let me see: I know I put that diaper bag you told me to pack somewhere." Several objects that should've been impossible to fit into a mane tumbled out as a result, creating quite the noise in the process.

Smarty Pants seemed to be utterly astounded, especially once she saw Boneless (or rather Boneless Two given the big red number two painted on the rubber chicken's belly) fall out and land on the floor. "How do you fit all that stuff in your mane, Pinkie?"

Whilst continuing to rummage around inside her mane, the pink party pony winked and said vaguely. "That's my little secret. I do lots of things nopony else seems to be able to do. I guess that's just what makes me me. Besides, with how often I've tried to style my mane, I feel like it almost has a mind of its own," Then, at last, she proudly proclaimed with great confidence! "Aha! Here we are! I knew I didn't forget to pack it!" Out from her mane emerged a comically oversized saddle bag that had her cutie mark printed on it. She set it down on the floor of the bedroom and opened it up, pulling out its contents one by one. "Diapers: Check," She tossed aside an entire box full of plain white diapers. "Foal powder: Check," Next to be removed was a large canister of the aforementioned powder. "Wipes: Check," A container of wet wipes was placed on the floor next to the diapers and the powder. "Rash cream: Check." The tube containing the cream was quickly set aside.

Twilight was absolutely amazed by how prepared Pinkie seemed to be. No doubt, her experience with the Cake twins had taught her well.

Pinkie just continued to empty out the incredibly large saddle bag. In addition to the diapers and the changing supplies, there was also jars of different flavored foal foods, a few foal toys such as rattles and squeaky toys, pacifiers in shades of baby blue and baby pink, and most surprisingly of all several baby bottles filled to the brim with milk (along with a mini-fridge to store them in). The pink party pony turned foalsitter then wiped the sweat from her brows. "Whew! That's everything." She said with great confidence.

Celestia smiled, satisfied with Pinkie's preparedness. "Indeed, all of this should be more than enough for the two of us," She said as she turned to Twilight. "Now don't worry, Twily. We'll only be this size until sunset. And I promise, next time I will ask before I cast an age spell on you."

"Okay, Mommy," Twilight nodded back, before asking. "So, what are we going to do on your day off?"

The regressed sun princess beamed happily, informing her fellow padded princess. "Well, today is far too nice of a day to stay cooped up indoors. So we're going to be going out to the park here in Canterlot."

At that the original padded alicorn let out a gasp as her eyes went wide! "But... but... everypony will see us! They'll get suspicious! My secret will be out! I'll be a laughing stock!" She shuddered and looked about ready to tear up.

Princess Celestia nuzzled next to Twilight, sweetly reassuring her. "Not to worry, Twily. I already thought of that when I was making my plans for today," Then she turned to Pinkie Pie and instructed. "Pinkie, if you wouldn't mind..."

Pinkie smiled. "Right!" She quickly pulled out a mirror, and held it before the regressed alicorns, thus showing them what they looked like. "See? Nopony's gonna recognize you!" Indeed, the mirror showed that the two padded ponies looked like ordinary unicorn foals: Twilight's coat was now a bright shade of pink, and her mane and tail were dark blue and void of the reddish-violet skunk stripe. Her eyes had changed to a sea green shade, and her cutie mark was no longer visible. Princess Celestia, meanwhile, appeared to be a pure yellow coated unicorn about the same size as Twilight, and with a plain white mane and tail. Her eyes were now a vivid shade of red.

That seemed to satisfy the formerly paranoid padded princess. Or at least it did until she thought of something else. "Won't ponies find it odd that two random foals can talk completely normally, though?"

Celestia chuckled. "No they won't, Twily. I not only cast a spell to disguise our appearances, but also a spell to hide our voices. To everypony not in the know, we'll just sound like normal foals speaking in foal babble. And nopony will find it odd if Pinkie talks to us as if she can understand us. Like you said, she already does things nopony else can do. So talking to foals and understanding them won't seem at all out of the ordinary."

"Exactly!" The pink party pony foalsitter happily declared as she put the mirror away! "So throw all those worries away, Twily! You and Sunshine Smiles here are going to have the best day out you could ever imagine!"

"'Sunshine Smiles'?" The sun princess blinked.

Pinkie Pie grinned and giggled. "Why not? Twilight's going to be Moonlight Beams. I figured you could both use names that nopony will suspect while we're out and about. Of course, you two can talk to each other normally, I'll be the only one who knows what you're actually saying," She playfully patted her charges on the forehead. "Now come on: This day's not gonna last forever, you know! Let's get you two ready for a day of fun at the park. And remember: If you need anything, just ask me. It's what I'm here for."

With the arrangements having been explained, Pinkie thus wasted no more time. She took hold of both regressed padded alicorns, then plopped them down into a double seated stroller that had an extendable canopy to block out the sunlight (thus keeping it out of the regressed princess' eyes). Once she had buckled them in and ensured they were secured, she then went about repacking all the supplies into the diaper bag before strapping it securely around her haunches. "Okie dokie, we're all set!" She happily declared with a smile.

"Ready to have fun, Twily?" Princess Celestia whispered to her former student.

Twilight nodded ever so slowly, part of her was still unsure and was worried that the age spell and everything related to it might fail. She would've much preferred casting it herself, so as to ensure there was no chance of that happening. But the situation was out of her control. So she just clutched Smarty Pants tightly.

Pinkie then pushed the stroller with the padded princesses inside of it through the castle hallways, past the seemingly endless maids, guards, and other castle staff that waved and cooed at the foals inside of the stroller (not one appearing to recognize who the foals actually were). At last, she reached the castle courtyard and with one more push she wheeled the stroller out onto the streets of Canterlot proper. She took great care in not pushing too fast and thus worry her charges needlessly.

Everything seemed to be working out just fine so far. Despite how ponies passed Pinkie and the princesses by, not a single one of them said or did anything that conveyed they were at all aware of what was going on. Most seemed to pay no real attention to the pink party pony turned foalsitter, and even the few who did made no comment about the foals that suggested that any of them recognized the foals' true identities.

"The spell is working, Twily," Smarty Pants whispered after a while. "This is perfect! You can be as much of a foal as you want, and nopony will ever know except Pinkie and our big sister over here."

The regressed padded alicorn let out a small sigh of relief. "Yes, it appears that we truly are disguised. I guess I shouldn't have doubted big sissy. She really knows her stuff when it comes to these complicated spells."

Then the earth pony foalsitter with a pretty pink coat leaned down briefly and whispered to the disguised princesses. "How are we doing, my little ponies? Does anypony need a break?" She sniffed the air, only to detect no strange smells. "Doesn't smell like anypony needs a diaper change just yet."

"You'd really be okay with changing my diaper, Pinkie?" Twilight questioned. For whatever reason, that felt so odd to her even though she'd had it done when Pinkie had been her playmate.

Pinkie Pie firmly nodded. "Hey, it's what foalsitters do. After all, you're not old enough for the potty yet. So if you have to go, just go. Do whatever you need to do, and I'll change you afterward. You don't have to worry about a thing, okay?"

Apparently satisfied with such a statement, the younger padded princess nodded back and then leaned back into the stroller. It seemed like it was still a ways to the park, so she started to close her eyes in the hopes of catching a little shut eye for however long the journey would take.

However, it was at that very moment that none other than Prince Blueblood happened to come walking by. As soon as he spotted Pinkie and the stroller, he frowned and approached her with his snout held high in the air in disapproval. "Whatever are you doing here?!" He hissed. "Don't you have that silly little bakery back in Ponyville to run?! Or did somepony invite you here to throw a rather childish party?!"

The pink party pony protested in reply. "Isn't it obvious? I'm here to foalsit these little ones," She briefly gestured to the stroller. "You probably don't know this, but I can be very responsible when I want to be!"

Blueblood humphed. "I sincerely hope you didn't steal those foals, not that I particularly care," He eyed the foals and frowned in disapproval at them. "Little ones are so utterly annoying! It's bad enough ponies want me to actually kiss their babies! But at least I don't have to actually care for them at all! They are noisy, smelly, and very bad mannered! And of all the foals I've had the displeasure of coming across, these ones seem especially ugly!"

At that, a loud wail could be heard coming from the stroller! In spite of her best efforts not to do so, Twilight couldn't keep from crying! She figured the prince probably wouldn't be saying such comments if he knew who she really was, but they stung just the same.

Princess Celestia, for her part, just leaned over in the stroller to comfort Twilight and whispered. "It's okay, Twily. Don't mind my nephew. He's just being a brat," She let out a sigh and humphed. "Like he usually is, unfortunately." She already made a mental note to discuss his behavior with him the next time she saw him, albeit without letting him know that she had been a direct witness to his latest bout of bad behavior.

Blueblood seemed to overhear the foals babbling, and rolled his eyes in annoyance. "Oh, excuse me," He sarcastically quipped. "It is hardly my fault if I find you foals to be far from pleasing. It's bad enough I have to deal with being snubbed yet again upon learning that my Aunt Celestia has preferred my Aunt Luna instead of me to run the country in her absence. Having to deal with such nasty foals as you is enough to make my fur crawl. Rest assured, you will most certainly not be getting a kiss from me today, little ones."

"Don't you have anything better to do, Prince Blueblood?" Pinkie Pie frowned in reply. "You're making my foals all upset. It's like you have no manners at all."

The prince snorted and swished his tail! "I don't need a lecture from a pony like you who trashed the Grand Galloping Gala alongside her friends! I have no idea how it is that you could defeat such threats as King Sombra or Queen Chrysalis, nor do I particular care. Far as I'm concerned, you are all unworthy," Then he stomped his hooves down. "Besides, you would do well to teach your foals to watch their tongues when they are in my presence. At least when I was growing up, foals were taught to respect their elders," Right as he finished speaking, he sniffed the air and recoiled and gagged as an all too familiar foul stench assaulted his ill prepared nostrils! "Ugh! Now they even have the nerve to soil themselves before my very eyes!"

Pinkie, undeterred by the smell, just replied. "I'm sure they didn't do it on purpose," Under her breath she muttered. "Though it would serve you right after talking about them so badly."

"What was that, young mare?!" Prince Blueblood inquired. "Speak up, I didn't quite hear you."

The pink party pony hastily corrected. "It's nothing! But I should probably get them changed before they get a rash! So why don't you just go do... something princely somewhere else?"

Blueblood firmly nodded. "That is the first good idea you have ever had, Miss... whatever you said your name was. I would at least bid you a good day, but we both know my day has been anything but good," He then trotted off, rolling his eyes again and remarking to himself. "I've half a mind to give such disgusting foals a royal flush! At least then I wouldn't have to put up with their nasty behavior!"

As soon as Prince Blueblood was out of sight, Pinkie bent down in the stroller and spoke sweetly to them to call them down. "It's okay, he's gone now. I'm sure he probably didn't mean all those nasty things he said. He was probably just in a bad mood," She put a hoof to her chin. "It seems like he's always in a bad mood. For a grown-up pony like him, he acts as if he's no better than a spoiled foal."

"Believe me, you don't know how tempted I was to regress him into a foal right on the spot," Princess Celestia declared quite firmly. "And I'd say it serves him right that we messed ourselves right in front of him! Rest assured, he will be punished severely for his bad manners the next time I see him."

Twilight giggled. "If you do turn him into a foal, you should be sure to give him lots of spankies! He definitely deserves them!"

Celestia snickered. "I'll keep that in mind, Twily."

"Not to change the subject," Smarty Pants spoke up as a hoof rested over her nostrils. "But can we please get you two changed already?! You're stinking up the stroller, and I don't like it! I can handle one smelly baby, but two stinky foals is a little too much!"

"Oh, right, I almost forgot," Pinkie Pie said rather sheepishly, blushing a bit as she unbuckled the two regressed alicorns and took them into her hooves. "Come on, let's find a place to get you two stinky fillies changed," As luck would have it, the stroller had stopped almost right in front of a small ice cream shop. And that gave the foalsitter an idea. "Tell you what:" She said to them. "If you two don't make a fuss during the diaper change, we can get ice cream afterwards. How's that sound?"

Twilight happily clapped her hooves and cheered! "Yay, ice cream!"

"Sounds lovely to me." Princess Celestia chimed in with her own sentiments.

Pinkie thus wasted no time in carrying the two stinky princesses into the shop, and immediately made a beeline for the mare's restroom at the back. Once inside, she placed her smelly charges atop the changing table and set the diaper bag down before opening it up. She then reached into her mane, quickly pulling out some rubber gloves and a clothespin (which she placed over her nose). "Okie dokie lokie," She said as she took several deep breaths. "Time to get you all cleaned up. Hold still, please."

Luckily for both Twilight and Princess Celestia, Pinkie's foalsitting skills had not diminished in the slightest despite how long it had been since she'd last tended to the Cake twins. She very quickly undid their soiled diapers and tossed them into a nearby trash bin. "Phew! What did you two eat that made you so stinky?!" She exclaimed while fanning a hoof in front of her face, making both princesses blush as their faces were flushed with embarrassment. Quick as a flash, she wiped them down, powdered them, and strapped them into brand new, spotless diapers. Then she took off the gloves and the clothespin, tossing both into the same trash she'd discarded the dirty diapers in, before washing her hooves and helping her now clean smelling charges down.

"Thank you, Pinkie!" Twilight breathed a much needed sigh of relief. "I'm sorry I didn't warn you ahead of time how bad it was going to be."

The pink party pony waved a hoof, dismissing the concern. "Oh, you couldn't help it, Twily. You're a foal, and foals wet and mess their diapers a lot. Besides, your dirty diaper wasn't that bad, and neither was Princess Celestia's. It's nothing compared to the first time I had to change Pound and Pumpkin Cake."

Celestia, meanwhile, just said. "I've more than gotten used to how stinky you can be, Twily. And now you know that even big sisters can have accidents too. So there's nothing to be ashamed of if you have a stinky accident or two from time to time. It doesn't mean I'll love you any less."

"Exactly!" Pinkie Pie beamed! "Now come on: A deal's a deal, so we're getting ice cream. And then it's only a short walk from here to the park."

After the detour for ice cream (Twilight and Celestia both got vanilla, and Pinkie Pie got strawberry), it was indeed not far at all to reach the park. By now, the sun was high overhead, and the park was packed with foals and their parents, some strolling along in silence and others running about while screaming and cheering in delight.

"Alrighty, my little ponies!" Pinkie happily cooed as she wheeled the stroller right into the middle of the park, stopping by a small playground. "Here we are!" She unbuckled her charges and set them down on the outskirts of the playground whilst she sat on a nearby bench. "Go on: Go play and have fun. I'll be right here if you need me."

Princess Celestia then encouraged her fellow padded princess! "Come on, Twily! You heard what Pinkie said! There's so much fun waiting for us. And you already know nopony but Pinkie's gonna recognize us."

Smarty Pants encouraged as well! "Yeah. It's not every day you get to go to the playground. There's so much to see and do: Slides, swings, seesaws, you name it! I can't remember the last time we had that kind of fun together!"

So Twilight somewhat hesitantly waddled along, Smarty Pants resting firmly on her back and occasionally looking back to make sure the doll hadn't fallen off. Everything else today had gone smoothly, her identity and her secret hadn't been exposed.

The two regressed princesses had only taken a few steps onto the playground, when suddenly it was as if every foal within a five mile radius had become aware of the newcomers' presence. One foal with a sky blue coat and a vibrant orange mane and tail all poofy waddled up to Twilight and Celestia. "Hi," It greeted in an obviously female sounding voice. "I Sky Streak! Was your names?"

With practiced precision, Celestia gestured to herself and to Twilight and said. "I'm Sunshine Smiles, and this is my friend Moonlight Beams."

Sky Streak briefly eyed the two foals, before smiling and extending a hoof. "Nice to meet ya. Ya new here? I not seen either of ya before."

The regressed alicorn with a majestic white coat nodded. "Uh-huh. We just moved to Canterlot not that long ago. Our mommies and daddies work at the castle!"

"Ooh!" Sky Streak exclaimed with starstruck wonder. "Do ya get to see the princesses and the royal guards?"

Princess Celestia happily nodded. "Uh-huh. We see them all the time. Isn't that right, Moonlight?"

"Huh?" Twilight blinked, before hesitantly and nervously answering. "O-oh, yes. They're lots of fun to play with. We especially like to play hide and seek with them, and we're always hiding. One time, we hid ourselves so well they had to search the whole castle just to find us!"

Sky Streak then eyed the well worn doll resting on Twilight's back. "What's that ya got there? Looks like some old doll."

The younger padded alicorn lifted Smarty Pants off her back and held it in front of her. "Oh, this is Smarty Pants. She's not just a doll, she's my best friend! Say hello, Smarty Pants."

Smarty Pants spoke in a very obviously exaggerated voice. "Hello, I'm Smarty Pants. Nice to meet you, Sky Streak."

Sky Streak eagerly shook the doll's hoof. "Is nice to meet ya too, Smarty Pants," Then she turned her attention to the princesses (though she clearly didn't recognize who they actually were) and said to them. "Come on: I gotta introduce ya to the rest of the crew! This our playground, we all meet here to have fun together! And now ya one of us! We always got room for new playmates!" Happily kicking her back legs, she waddled off towards the other foals all scattered across the playground.

The regressed sun princess smiled anew, taking her fellow padded alicorn firmly by the hoof. "Come on, Twily! No turning back now! Let's go have some fun!"

Twilight followed, still just a little bit hesitant. But one look back to Pinkie Pie (who gave a silent, encouraging nod) erased any doubts she might still have. For however long she would remain like this, she very much wanted to make the most of it.

The rest of the day was a fun filled blur for both regressed padded princesses. Neither could recall the last time they'd had so much fun with others: Whether it was going down a slide, swinging on the swings (with Pinkie pushing them as needed), bouncing up and down on the seesaw, spinning round and round on the merry-go-round, or just running up and down the steps and throughout the length of the playground equipment. The fun was only interrupted on occasion when Pinkie Pie would subject them to unannounced diaper checks, and more often than not change them at a nearby park restroom.

Everypony was having so much fun throughout the day that hardly any of them were paying attention to the passage of time. Alas, the sun eventually began to grow lower and lower in the sky. And with sunset approaching, it was time for everypony on the playground to go their separate ways.

Pinkie quickly scooped up Twilight and Celestia, buckling them into the stroller as she cooed. "Good job keeping those diapers clean this time."

"Sorry we made you go through so many of them, Pinkie," Twilight blushed anew as she and Celestia settled in for the ride back to the castle. "I guess we were just too absorbed in playtime to notice when we were wetting and messing ourselves."

"Or maybe it's just a sign that the spell was working as intended. Foals don't always know when they have to go," Princess Celestia replied. "Plus, it really did make me feel young again. It did make you feel young again too, Twily?"

The padded princess nodded. "Yes, even more than usual."

The pink party pony just smiled as she pushed the stroller along. "Well, this was definitely a blast from the past. If you two ever wanna do this again with anypony, you just let me know. I'm happy to be the foal or the foalsitter."

The younger padded alicorn replied. "True, you are good at being both," Then she thought of something that had only just now come into her mind. "But if you were here today taking care of big sis and me, who was watching Sugarcube Corner back in Ponyville?"

Pinkie Pie chuckled. "Oh, that's easy, silly. Maud was doing it. She was already staying close to Ponyville as it was, something to do with a dig in Gastly Gorge, I think."

And Twilight questioned. "Did she say anything at all... unusual?"

Pinkie shot Twilight a most puzzled look. "What do you mean? She seemed to be her usual Maud self, maybe a little bit happier."

The padded princess just shrugged her hooves. "Nevermind, forget I said anything." If Maud hadn't told Pinkie about that other side of her, Twilight wasn't going to tell. It wouldn't be right for her to blab about somepony else's secret after all the ponies who'd been entrusted with keeping her secret.

As for Princess Celestia, she was thinking quietly to herself. All in all, her day out with Twilight had been thoroughly enjoyable. Aside from the encounter with Prince Blueblood, there had been nothing that stood out as an immediate cause for concern. Well, that is except for how much it seemed Twilight was apologizing for everything she did while regressed. That stood in stark contrast to all the times when Twilight had seemed content to act as a foal to the fullest extent possible when in the sun princess' care.

Celestia made a mental note to bring this up whilst helping Luna with her duties at night. At the very least, Luna could hopefully reassure her that she was overthinking things and that there was nothing to be worried about.

"Well, here we are!" Pinkie Pie said at last as she pushed the stroller right up to the castle gates and brought it back inside the confines of the castle. She then quickly led them back to the bedroom Twilight so often frequented during her stays, and just in time as the spell Princess Celestia had cast wore off only seconds later.

"You can go back to Ponyville, Pinkie Pie," The sun princess reassured the pink party pony whilst removing the diaper wrapped around her rump. "I can manage on my own from here."

Pinkie gave a salute and nodded. "Gotcha, Princess Celestia! But if you ever need my help again, you know how to reach me." Then she bounced away with an exceptionally bright smile on her face.