Mrs. Cake was as good as her word. The very next day, she and Mr. Cake went out with Pinkie to shop a foal supply store near the edge of Ponyville for their new little one. Pinkie was still very self conscious about shopping for her newly discovered interest in being an adult foal, so the Cakes brought Pound and Pumpkin along for cover (they needed to pick up some more foal supplies for them anyways).

After a little bit of wandering around and picking up standard foal supplies: Diapers, changing supplies, bottles etc…At the checkout counter, the Cakes split off. Sensing that Pinkie would feel more comfortable around Mrs. Cake, Mr. Cake opted to stay behind with the twins and wait for them near the checkout counter.

Mrs. Cake just smiled as she led Pinkie along down the diaper aisle and whispered, "You can't be stealing diapers from the twins, Pinkie. That's not right. Besides, you need diapers that fit you."

Pinkie felt as shy as Fluttershy, she was looking all around in fear that somepony she knew was going to spot her. "But I don't know where to go or who to ask. I couldn't risk doing it myself and having you either or Mr. Cake find out."

Mrs. Cake simply stroked Pinkie's mane, calming her down. "Everything's going to be okay, Pinkie. Mommy's here for you now, and she'll make sure nopony makes fun of you. Let's just ask one of the workers here and see if they can help us."

The two earth ponies approached a cobalt blue coated unicorn stallion with a light brown mane and tail, he had green eyes, a cutie mark involving some bits, and wore a white apron uniform. "May I be of assistance, ma'am?" He innocently inquired.

Mrs. Cake cleared her throat. "Yes. I was wondering if you by any chance had..." She paused and whispered. "Diapers."

"We have plenty of diapers here at the store, ma'am. Are you looking for a particular brand?" The stallion inquired further.

Mrs. Cake leaned forward and whispered into the worker's ear. "Do you have anything that could fit a fully grown mare?"

The stallion was silent for a moment and blinked his eyes. The suspense did nothing to help Pinkie's already frail nerves. But the silence faded as the worker just grinned. "Got yourself one of those forever foals? Well lucky for you, we've got a fine selection of adult sized diapers and foal supplies for such unique clients. Please, follow me."

The stallion led Mrs. Cake and Pinkie Pie to the back of the store, through what appeared to be a wall but actually turned out to be a well crafted illusion. A huge warehouse like structure greeted their eyes as the two mares took in their surroundings.

The shelves were lined with a huge assortment of custom diaper brands, all designed to fit much bigger foals. A row of different colored pacifiers in all sorts of shapes and patterns hung off to one side. And there were toys that looked like sized up toddler toys. To say nothing of the huge collection of adult sized dresses and sleepers that were all clearly designed for somepony wearing a diaper.

Mrs. Cake was amazed! She never would've expected the world of adult foals could be this big. "My goodness! So many options!"

Pinkie Pie was speechless! This was something she could only dream about, but now it was real.

"How long have you had your new big little one?" The store clerk smirked as he asked Mrs. Cake.

"Oh, I just found out the other day, actually. This is my first time shopping for her," Mrs. Cake's cheeks reddened as she explained and waved a hoof. "Pinkie is very nervous about all of this to be honest. She just recently started getting in touch with her inner foal so to say."

The store clerk smiled. "Well, if she's just starting out, might I recommend our adult foal starter kit? It's got all the basics one could need for a big foal. A medium pack of Silly Filly adult brand diapers with customizable prints, changing supplies, some toys, a bib or two, and a sleeper so the little one has something to wear for those chilly nights. We also include three pacifiers at no extra charge. And first timers get a discount. This normally can go over for one hundred bits, but you can have it all for just thirty five!"

Mrs. Cake looked across to Pinkie, seeing the pink party pony's eyes light up! With a nod, she turned to the clerk and told him. "We'll take it!"

"Very well then," The clerk nodded in reply and clapped his hooves, summoning a bunch of workers. "One starter kit with the works. You know the drill!" Then he trotted over to a nearby register. "Your order will be filled shortly. Now if you'll kindly pay up."

A short time later, with the supplies in tow, Mrs. Cake and Pinkie Pie left the secret warehouse. Thankfully, the items were all bagged, so it was impossible to tell from afar what they were as the mares reunited with Mr. Cake and the twins.

Immediately upon returning to Sugarcube Corner, Mrs. Cake told her husband. "I'm going to take our new foal upstairs to get diapered. You can handle the twins and running the store for me, right?"

Mr. Cake nodded and kissed his wife on the cheek. "Alright. I'll come up later on and we can swap roles. Then after today, we can work out a proper schedule to take care of our newest little one," He smiled as he looked at Pinkie. "Don't you worry, Pinkie. Mommy will take good care of you, and Daddy promises he'll be up later. So be a good little foal, okay?"

"O-okay." Pinkie replied with a gulp. It was still so weird to think that her secret was not only out, but now the Cakes were helping her to indulge in it. She'd never done this with anypony before.

Mrs. Cake led Pinkie up the stairs with the foal supplies in tow. "You sure you really wanna do all of this? You'd really diaper and take care of a full grown pony?" Pinkie asked her.

Mrs. Cake simply laughed. "It'll be just like taking care of the twins, only with a much bigger foal," She fondly added. "Besides, you're already family to me and to Carrot. From the day I met you and took you in, it was like you were a daughter to us. I didn't think I'd ever have more foals after Pound and Pumpkin were born. But now I get to be a mommy all over again. And this is one foal I know won't outgrow me."

Pinkie blushed. "You really mean it? I know this must be a lot to take in. It still feels so weird."

"You already do a lot of weird things, Pinkie. And Carrot Cake and I love you just the same," Mrs. Cake reassured her charge. "Now stop worrying. You just relax, and let Mommy and Daddy take care of everything."

Pinkie gave a nervous nod and whispered. "Yes, Mommy." She blushed a little upon saying those words. Even though she loved her own mom, Cloudy Quartz was never as maternal or sweet as Mrs. Cake. She'd secretly always wanted Mrs. Cake to diaper her and baby her like one of the twins from the day she'd met the baker almost fifteen years ago.

As Pinkie Pie was lost in thought she soon arrived in her bedroom as Mrs. Cake spoke up. "We'll have to see about setting up a nursery of some kind for you up here. I'm sure we can buy that stuff at the Foal Super Store. You can't exactly borrow the twins' nursery, it's not big enough for you."

"Y-yeah, I don't think I could fit into a crib or on a changing table." The pink party pony admitted. Why did those things sound so strangely appealing? She wasn't even sure she was going to like being babied, even if it was by someponies like the Cakes. This was all so sudden. And there was still a part of her that told her this was wrong.

Mrs. Cake blushed as she explained further. "Well I did see an ad at the store saying they were having a sale on adult nursery makeovers for adult foals. We can discuss that later when you're feeling more comfortable."

Then Mrs. Cake motioned for Pinkie to lay down, and then she opened the package and brought out the diapers. She unfolded one, smiling at the fact that they were the same lovely shade of pink as her new foal's coat, and had blue and yellow balloons printed on the crinkling padding to serve as wetness indicators. With practiced precision she was able to slip the crinkly, poofy padding under Pinkie's rump, thread the tail through the hole in the back, and fasten the pink tabs across the sides. Then she worked in a generous helping of foal powder, before helping her little one to stand.

For a moment, Pinkie just stood there, unsure of what to do or how to feel. The diaper felt just as thick to her as the inflated one she'd briefly put on yesterday. But this was a more natural, reassuring kind of thick. As warm and embracing as a hug. And the lovely scent of foal powder soon permeated the area. It was one that Pinkie just loved after changing the Cake Twins.

To complete the look, Mrs. Cake gave Pinkie a pacifier similar in color to the one her husband had mentioned seeing Pinkie suckle on. She let out an aww when she saw how cute Pinkie now looked in her new, infantile state. "Oh, you're so cute, I could just eat you up."

Pinkie said nothing, she just suckled on her pacifier as she enjoyed the soothing sensation it gave her.

Not one to be content as just an observer, Mrs. Cake opted to dig into the bag and pull out some toys. She pushed forward some alphabet blocks, offering them to her big foal. "Why don't you show Mommy how smart you are? Can you spell 'Mommy'?"

Pinkie nodded. With the pacifier in her mouth talking was difficult and embarrassing. She sat down on the floor, causing her padding to compress and a cloud of foal powder to billow out from the leg holes. She giggled at the sensation, opting to more or less crawl along the floor towards the blocks, making her diaper crinkle adorably.

She pretended to have trouble at first figuring out what to do, slowly arranging the blocks in no particular order. Then, eventually, she was able to stack them atop each other so that they spelled out 'Mommy'! "Tada!" She declared, standing up and acting like she was quite proud of herself.

The plump baker cooed. "Very good, Pinkie. You're so smart! Who's Mommy smart little foal? You are. Yes you are."

Pinkie giggled again. "This isn't so bad so far," She thought to herself. "I think I actually might come to like this whole 'Adult Foal' thing."

Pinkie and Mrs. Cake played happily together for quite a while. Neither one kept track of the time. But eventually, Mr. Cake came trotting up to Pinkie's bedroom. He smiled and watched the two having fun together for a moment, before he cleared his throat. "Sugar plum, it's your turn to watch the twins and run the store. I'll take over watching our new baby."

Mrs. Cake stood up. "Thank you, honey bun. See you later."

Pinkie waved to Mrs. Cake as the plump baker departed. "Bye, Mommy!" She called out with the pacifier muffling her voice a little.

Mr. Cake just cooed as he approached the big foal. "Okay, Pinkie, Daddy's here to play with you."

"Yay, Daddy!" Pinkie cheered, giving the stallion a hug.

Mr. Cake returned the hug, then grinned. "Well, you know what Daddy likes to play with his foals?" Pinkie shook her head. "Tickle monster!" The stallion declared as he gently pushed Pinkie to the floor, rolling her onto her back.

"No, please, stop!" The big foal pleaded in vain, she was extremely ticklish!

Mr. Cake ignored the pleas, tickling Pinkie all over her hooves and watching her kick in delight. After a little bit, he stopped to let his foal catch her breath. "Time for my secret weapon!" He declared as he took in a big breath of air.

The pink coated mare realized what was going to happen! "Don't!" She protested only slightly, knowing full well she was powerless to stop her daddy.

The lanky stallion lowered his snout to Pinkie's chest and blew long and hard, bombarding her with a raspberry assault!

Pinkie howled with laughter and kicked some more! Her eyes started to water from laughing so hard. But all of a sudden, as she was laughing and kicking with glee, she felt something move inside of her. Next thing she knew, there was a faint hissing sound. A damp patch started to form on her diaper, but it was growing rapidly as the seconds ticked by. She let out an eep upon realizing what was happening, and crossed her hind hooves in a failed attempt to stop it!

Mr. Cake stopped the attack as the hissing reached his ears. Having raised two children, he knew from experience what that sound meant. He did his best to give his foal privacy until she'd finished. "My goodness, looks like somepony really had to go!" He declared.

"W-well, Mommy gave me a bottle earlier. I guess it went right through me." Pinkie admitted with a blush.

"Guess we'd better get you changed. Don't want my foal to get a rash." Mr. Cake commented as he retrieved some wet wipes, foal powder, and a new diaper.

Pinkie cooperated as her old diaper was un-taped, bailed up, and tossed aside with some delicate hoofwork from Mr. Cake. Then she felt the cold touch of the wet wipes as they made contact with her fur, she almost shivered.

"Oh, I'll bet that feels cold, doesn't it?" Mr. Cake guessed and got an answer when Pinkie nodded. "Well don't worry, I'm almost done. Just try to hold still, okay?"

The big foal obeyed. Sure enough, a few seconds later the wet wipes were discarded and a new diaper was fastened around her. Just like before, a generous helping of foal powder was sprinkled in when it was all over.

"I'm gonna go put this in the trash and wash my hooves," Mr. Cake told Pinkie as he picked up the old diaper and the wipes. "You stay here. I'll be back shortly. Then I think we'll go downstairs for lunch, and see what sort of delicious num-nums are on the menu for today."