Pinkie could hear her stomach growling by the time Mr. Cake came back upstairs to get her. "Okay, Pinkie, let's get that rumbly tummy of yours satisfied." He said to her.

But Pinkie didn't want to move. "There'll be ponies downstairs, they'll see me like this! Everypony will surely laugh, or take pictures, or laugh and take pictures, maybe all at once! Please, don't make me go downstairs! Can't I just have lunch up here? I promise I won't make too much of a mess."

Mr. Cake tried hard not to laugh as he told Pinkie. "You have nothing to worry about. Mrs. Cake already took care of that. She put up an 'Out to Lunch' sign, nopony's going to be downstairs except for you, me, her, and the twins of course."

"You really think it's a good idea for them to see me like this?" Pinkie questioned as she poked at her padding with a hoof. "I mean, they're at that age where they're not supposed to be wearing diapers anymore."

Mr. Cake grinned. "What, do you think they'll be jealous? You can serve as a role model to them. And that way they won't feel too bad whenever they're still in diapers," Then he approached Pinkie. "Now come on, you must be starving!"

Pinkie had to admit that she was getting awfully hungry. She knew that in her current state she probably wasn't going to be allowed to feed herself, but the big foal didn't mind too much. It was all part of the act, the whole intent of being an adult foal and acting out as such in the presence of a caretaker (or caretakers in this case) was to feel relaxed, carefree, and innocent.

So the two earth ponies made their way downstairs, Pinkie still opting to hide behind Mr. Cake as they reached the bottom step and headed towards the kitchen, just in case there might be a stray pony or two that hadn't left yet. There wasn't a pony in sight, Sugarcube Corner was completely deserted.

In the kitchen, Mrs. Cake had already strapped Pound and Pumpkin Cake into their high chairs and tied bibs around them. She was currently trying (and failing) to feed them their lunch, which consisted of some kind of orange flavored foal food. Noticeably she had small traces of the stuff splattered on her face, and some on the bars of the high chairs.

"Seems like Mommy's having trouble with the other foals," Mr. Cake observed. "I guess I'll have to take care of feeding you, Pinkie. Sorry we don't have a highchair for you, yet. I'll place an order for one from a furniture store in Manehattan first thing tomorrow. And don't worry," He reassured Pinkie as he helped her sit down in a chair at a nearby table. "I'll make sure the order is anonymous." Then he tied a bib the same pink color as his new little one's coat around Pinkie's neck.

Mrs. Cake came over with a sigh. "Thanks for getting Pinkie all set up, honey bun. If only the other foals were as cooperative. I don't know why, but today they've been nothing but trouble," She eyed a cookie jar that rested out of reach on a shelf high above. "I think they want cookies."

"Sugar plum, you know they can't have them and nothing else. It's not good for them." Mr. Cake shook his head.

The plump baker nodded before she sighed again. "I know, and I don't plan to do so. But they just don't wanna cooperate with spoon feeding. I even tried to let them feed themselves, they won't do it."

Pinkie looked across to the twins, who were currently too busy giggling and eyeing the cookie jar to take any notice of her or her current state of appearance. A light bulb appeared over her head as she declared. "I can help with that! The twins need a role model, and I'm just the pony to do it!"

"You think that will work, Pinkie? You're not foalsitting them right now." Mrs. Cake commented with concern.

Pinkie just grinned as she gave a knowing wink to Mrs. Cake. "It's okay, this worked all the time on Marble and I when we were foals on the rock farm. Our parents always used Limestone and Maud whenever they wanted to show us how to behave. And sometimes, I'd be a role model for Marble if she wasn't cooperating. The twins already know me, so when they see you treating me like them, they'll see what cooperation gets you. And this way, you can feed me whatever you want."

Mr. and Mrs. Cake exchanged glances as they looked across to the twins, then back to Pinkie. "Well, I guess it's worth a shot," Mr. Cake declared. "You sure you're up for it? We don't need three foals making messes."

The pink party pony giggled and kicked her legs. "Come on, you know you can trust me. I haven't given you a hard time yet, have I?"

"Well, no, I guess not. You've been really good at playing along and cooperating." Mr. Cake replied to Pinkie.

Pinkie nodded her head. "Exactly! Now come on, enough chit chat! I'm starving! So make with the num-nums, and soon you'll be amazed by how fast the twins learn!"

So Mrs. Cake went back to retrieve the jar of foal food she'd been trying to feed the twins. Bringing the jar closer to Pinkie's location, it was now possible to read the label. The words Squashed Carrot were printed in large, colorful letters. And Pinkie's nostrils inhaled the delicious and inviting scent that wafted from the open jar.

Meanwhile, Mr. Cake had taken the liberty of whistling to get the attention of Pound and Pumpkin Cake. "Pound, Pumpkin," He called in his best fatherly tone. "Pinkie Pie has something she wishes to demonstrate. Isn't that right, sugar plum?"

Mrs. Cake nodded. "You're right, honey bun. Pinkie is going to show how you're supposed to behave when Mommy or Daddy try to feed you, regardless of what it is," She carefully dipped a spoon into the jar and brought the orange colored goop to Pinkie's mouth. "Open wide, here comes the aeroplane!"

The twins watched with wide eyed wonder as they saw the pony they looked up as an older sister open her mouth upon command. They briefly took notice of the huge diaper she was wearing (at least, it seemed huge to them), but their attention was soon drawn to what Pinkie did when the foal food was presented to her. She didn't grab the spoon and try to fling the goop back at Mrs. Cake. She didn't try to knock it away and spill the spoon's contents onto the floor. She just kept her mouth opened until the foal food was deposited onto her tongue. She then swallowed, savoring the sweet taste as it worked its way down her throat. "Mmm. Yum yum!" She declared, licking her lips.

Mrs. Cake couldn't help but giggle and coo. "That's right, Pinkie! Yum yum for your tum tum!"

Mr. Cake, meanwhile, told the twins. "See? Pinkie doesn't make a fuss. And you wanna be just like her, don't you?" Both foals nodded.

"Good," Pinkie declared as she finished swallowing the last of the foal food. "Because there's a whole lot more where this came from! It's like a whole world of flavor!"

The entire spoon feeding process repeated itself several times for the next several minutes, until the jar was empty and Pinkie's stomach was nice and full.

"Would you like a bottle to wash down your lunch?" Mrs. Cake offered Pinkie, who happily nodded in reply. A short time later, she was offering her new big foal a delicious, warm bottle of milk.

It didn't take much effort for Pinkie to grasp the bottle and suckle on the rubber nipple. Her efforts were rewarded with a rich, creamy taste as she slowly drained the bottle down to the last drop. Once she had finished, she removed the bottle with an audible pop and leaned back in her chair. Suddenly, she felt a rumble in her stomach, and then she opened her mouth and let out a belch. "Oopsie, excuse me!" Blushing as her cheeks turned a faint but noticeable shade of red.

The twins giggled and kicked their legs in amusement. "Big sissy siwwy!" Pound Cake teased.

"Yeah, she just wike us, onwy much biggew!" Pumpkin Cake added with a goofy and energetic grin on her face.

Both foals then started pleading together. "We wanna pway with big sissy! We wanna pway with big sissy!"

Pinkie's heart melted at the adorable comments. "Aw, you guys really wanna play with me? That's so sweet of you to offer. I'll do it!" Playtime would be much more fun with actual playmates. Any worries she may have had earlier about the twins seeing her all padded up had melted away. For she now knew that they saw her as being on the same level as them.

"Great idea, Pinkie! But first we'd better get you cleaned up!" Mr. Cake teased as he retrieved a wet rag. "Good thing Daddy put a bib around you. You're such a messy eater."

"Am not!" Pinkie playfully lied.

Mr. Cake laughed as he playfully retorted. "Are too! But that's okay, Mommy and Daddy love you no matter how much of a mess maker you are. Better on your bib and face than on the walls or your diaper."

After her face had been wiped clean and the bib untied, Pinkie followed the twins as they were led up to their nursery by Mr. and Mrs. Cake.

Since the playpen most definitely wouldn't fit a pony of Pinkie's size, she opted to sit on the floor instead. She didn't mind, her diaper gave her a nice, soft cushion to sit on. It was like having a pillow tied to your rump, only much more comfy and bouncy. And if you sat still, it was possible to have your rear sink into it, turning it into an instant bean bag chair.

"Whadya guys like to do for fun?" Pinkie asked the twins as they sat on the floor of the nursery next to her. She had a pretty good idea already from the many times she'd foalsat them. But this time she was more of a student than an observer, that meant having to take on a whole new role.

"Me wike to pway with pwushies, tey make good instuwments." Pumpkin Cake answered.

Pound Cake simply replied to Pinkie. "Me pway with bwocks or anyting I can knock ovew! But me awso wike to fwy, and sometimes sissy do it too!"

Pumpkin Cake giggled. "It espicawwy fun to fwy out of ouw cwib when we supposed to be sweeping. We used to do it aww the time, but now magic and wings hawdew to use so we onwy can fwy if we weawwy twy hawd."

"Well, I don't think your parents would approve of you trying to fly around the nursery. You always leave hoofprints on the ceiling and the walls," Pinkie replied with a shake of her head and put a hoof to her chin. "I got it! How about we play hide and seek?! That's loads of fun!"

"Otay!" Pound happily answered and fluttered his wings a put so that he was level with Pinkie's snout. He pushed a hoof to her nose as he declared. "You the seekew! We hide, and you come find us. And you no can ask Mommy ow Daddy fow hewp if tey show up."

"Yeah! You gots ta find us on ya own, big sissy!" Pumpkin firmly insisted. "We be faiw and onwy hide in pwaces ya can weach. We no twy to use magic ow wings to hide."

Pinkie smiled, hugging the twins. "Aw, you're such good sports. I couldn't ask for better playmates than you. Okay, you hide and I'll count to ten. Don't leave the nursery, though. I may be your big sister, but I'm also watching over you two while your parents run the store," Then she put her hooves over her eyes and began to count to ten slowly. "One... two..."

The twins giggled as they scampered off and split up to hide. They felt confident Pinkie wouldn't be able to find them, she didn't know all their favorite hiding places.

At last, Pinkie reached ten and took her hooves off her eyes. "Ready or not, here I come!" She called in a sing song voice. She tried to stand up, but the weight of her diaper pulled her back down with a loud flump!, causing another cloud of foal powder to billow out of her leg holes. "Whoa! I knew they were thick, but I didn't think they were this thick!" She slowly stood up again, her legs wobbling slightly. "Come on, I can do this! I wasn't having trouble before. And Mommy and Daddy weren't helping me."

The pink party pony eventually managed to adjust her movements enough to where she could walk, albeit with a slight but noticeable waddle. Fortunately, the nursery wasn't very big, so her waddle wasn't too much of a problem.

She soon found Pumpkin Cake hiding beneath a pile of stuffed animals. Pound Cake took more time to spot, but eventually she discovered the little pegasus hiding in a corner of the closet. "Looks like I win!" She declared to the twins, who immediately replied by tackling her into a hug.

"You awway win, big sissy!" Pound happily replied. "But tat why we wove ya so much! Ya awways so much fun!"

"And we wove ya even mowe now tat you wike tis!" Pumpkin declared. "Ya one of us!"

A clapping of hooves drew the attention of all three foals. They turned around to see Mrs. Cake entering the nursery. "Very good, little ones. Mommy is so pleased to see you all getting along," She then smiled as she approached. "Now, it's time for a diaper check. Who wants to be first?"

Pound volunteered. Mrs. Cake picked him up and inspected his padding, setting him back after giving him a pat on the head. "Dry and clean, such a good little foal." The same held true for Pumpkin.

Pinkie cooperated when it was her turn, but she still blushed a little when Mrs. Cake pulled back the seams of her padding and checked the seat of her diaper. "Uh, wouldn't I know if I did anything?" Pinkie nervously asked.

"Not if you were so into playing. It tends to happen to little ones from time to time, their bladders can be unpredictable," Mrs. Cake cooed. "But you're dry too, Pinkie. Such a good foal you are. Though, Mommy doesn't mind changing your diaper wiapers."

Pinkie gulped. True, she'd already wet herself once today, and it hadn't been so bad. But the thought of doing anything intentionally in her diaper felt...off to her. "I mean, I could do something if you really wanted me to. But it's hard enough having to change the twins when they do it. And I'm a full grown pony, so that'd be even harder."

"It's alright, Pinkie, I don't want you to do anything you're not comfortable doing," Mrs. Cake reassured her big foal. "Perhaps you'd like to show how big you are by using the potty? The twins could certainly use the example."

The pink party pony obliged. "Sure. I sort of have to go anyway. Better the potty than my diaper, right?"

After the bathroom break, the rest of the day flew by like a blur for Pinkie. She spent most of the time playing with the twins, stopping only occasionally to have either Mr. or Mrs. Cake check her diaper.

When nighttime rolled around, Mrs. Cake put the twins to bed, while Mr. Cake took the liberty of helping Pinkie into her new foal sleeper with cute yellow crescent moons printed on the fabric. It was not unlike the pajamas she wore from when Maud had been considering moving to Ponyville after getting her rocktorate. Except this outfit had extra room in the back to fit a diaper, including a hatch that could be zipped open or shut to make changes easier.

"There we go!" Mr. Cake said at last as he buttoned the last button on the front of the sleeper. Pinkie's pacifier dangled from a small string that hung from her neck. "You'll be okay sleeping by yourself, right? You can always come get Mommy or I if you need anything."

Pinkie yawned. "Okay, Daddy. Ready to go night night."

Mr. Cake smiled, helping Pinkie into bed and pulling the sheets up to her neck, before he popped the pacifier into her mouth. He then bent down to give her a goodnight kiss. Pinkie then slowly drifted off to sleep with the pacifier bouncing up and down in her mouth.

As Mr. Cake watched he thought to himself. "She really is an adorable foal. With her, it's like I've become a father all over again. And I'll bet Mrs. Cake feels the same way as a mother. It's funny, for a time, we thought Pinkie was the closest we were ever going to get to having a family. Now, it seems she's our new baby cake." The thought made him chuckle.