Twilight used her magic and levitated over a diaper the perfect size for a grumpy little filly, some powder to help Cozy Glow's bottom after being spanked. She thought about bringing some mittens so Cozy wouldn't be tempted to remove her padding, but she thought it would be better to let Cozy see what happens if she ever tried taking it off. "She's going to be in for quite the surprise! Foals shouldn't play with their diapers." She thought and levitated Cozy up a little bit to slide the purple colored diaper underneath the filly's rump.
Cozy Glow started squirming as the alicorn placed the diaper underneath her. Her breathing started to increase, she (needless to say) didn't like the idea of having to put diapers back on. Especially since she'd been potty trained for at least ten years. She could remember it had been a nightmare for her parents to potty train her, and now she was being put back into the very thing she thought she'd be done wearing.
Twilight got really annoyed with this squirming. "Cozy Glow, stop that this instant, unless you want another spanking from Dash!" She protested as Dash started to walk closer to Cozy.
Cozy found herself at a complete loss for words. She didn't want another spanking, that last one had been more painful than she thought and her rump was still sore. She finally managed to find the courage to squeak out. "I... uh, no I don't. I… I'll be a good girl, I swear." And so she sat completely still for Twilight and let the headmare finish the diapering job.
Twilight smiled and put the powder over Cozy Glow's rump, then taped the diaper up snuggly around her waist. She helped Cozy up and gave her a small pat on the rump. "Aww, you look so adorable in your new diapers Cozy. Now let's get your pacifier in, shall we? If you're going to wear diapers, you might as well look the part." Cozy simply pouted and folded her hooves. How had she ended up in this situation?
Pinkie Pie, meanwhile, hopped over and just for the sake of it checked to see if Cozy Glow had used her diaper. Everything seemed okay. "Huh, I could've sworn I heard a hissing noise coming from this. Oh well, must be my imagination. Even the twins don't need diapers anymore. Don't worry, the foal's still clean, Twilight," She said all at once, saluting her friend. "But if she needs a change and you need some pointers, just ask me. I have plenty of experience foalsitting Pound and Pumpkin Cake."
"What do you think you're doing, you idiot? I know how to use the potty!" Cozy Glow snapped. "I don't need these stupid things!" And she slapped Pinkie's hooves away.
Then Cozy started to notice there were a lot of toys in this place, many of them designated for her. She felt like it was a little too much, not even a foal would be able to play with all those toys. Her thoughts were interrupted as a small, purple colored pacifier was shoved into her mouth, making her lose her train of thought.
"Wow, somepony's grumpy," Pinkie commented. "Nopony likes a pouty baby."
"Pinkie's right," Twilight spoke up. "And since you're going to be a baby, Cozy Glow, you might as well act the part. But first, let's get the rules taken care of. Now sit down and hear me out, Cozy, unless you want to sit on my lap while I read the rules to you?" She asked in an almost motherly tone.
Cozy Glow looked at her new guardian with disgust. "I absolutely refuse to sit on your lap!" She hissed and sat down on the floor. The new rules couldn't be that bad, right?
Twilight smiled at the cooperation. "She'll come around to this stuff eventually, I hope," Twilight though, hoping Cozy Glow would be a good girl one day (now that's what she was looking forward to the most). She levitated her short list of rules for Cozy Glow to her as she thought. "She's going to hate us for this, but it has to be done!"
"Okay, Cozy. The first rule is: You have to go to bed when we tell you to. That means no hissy fits, no temper tantrums, no buts or what ifs about it, and no exceptions. The second rule is: You will from now on drink out of baby bottles and eat only what is served to you. If anypony catches you trying to eat or drink from the grown up plates and cup, you will be put in the timeout corner. And the last and most important rule is: You have to use your diapers, at least until you can prove to us that you're learning. But if you're good you might be able to use the potty again someday," She instructed as she put it away and walked over to Cozy Glow as she smiled. "Now please try to listen and be a good girl, okay?"
Cozy Glow got up and out of anger slapped Twilight, there was no way anypony would make her use only her diaper, that was insane! "There's no way I'm going to use my diaper! You might have me in diapers but that doesn't mean I have to use them!" She screamed, only to be levitated by Twilight's magic.
"Cozy Glow, bad girl!" Twilight scolded. "You do NOT hit ponies! She walked over to the timeout corner and placed her young charge on a stool, plopping her down as her diaper was sure to put a magical strap over her so she couldn't escape. "Now sit here for ten minutes and think about what you've done, baby." She instructed and then decided to check up on Starlight Glimmer to brief her on the punishment.
Not long after Twilight left, Cozy Glow tried to escape. As she did so her diaper crinkled and she blushed deeply. "The moment that dumb alicorn lets me go, I'm going to rip this stupid diaper off and throw it in her face!" She declared, before she noticed the pacifier Twilight had given her was on the floor. Although she didn't really want to do it, the filly wondered if a pacifier would soothe her. It was better than sitting here with nothing to do, that stupid magic strap held her more or less in place. Reluctantly she reached down, put it in her mouth and suckled on it for a few minutes. "Huh, I guess this isn't too bad…" She unknowingly said aloud as a flash of light not unlike that from a camera hit her! She spun around and saw that Pinkie Pie had taken a picture.
"Aw, little Cozy Glow is enjoying her paci. I'll be sure to put this up on the wall to show Twilight," She cooed and put the camera away. "Now be a good girl, Coz. There's only five minutes left and then you're free to move."
Twilight returned shortly with Starlight, having filled the unicorn in on Cozy's punishment and what it entitled. "So, Starlight would you mind watching over Cozy Glow tomorrow?" She asked. "I have to visit the princesses and tell them everything that's going on, as well the punishment we'll be giving Cozy. It's certainly better than sending her to Tartarus for life." She said with a bright smile.
"Okay I guess," Starlight replied. At least as a diapered foal Cozy didn't seem like she would be able to cause anymore harm. "Maybe could I dress her up and take her out to the park?" She suggested. "I think she'd like her new situation more if she was around other foals," She waved at Cozy Glow. "I must admit, those diapers do look good on her."
"I know, I had no idea foal stores were in on my popularity too," Twilight giggled. "And dressing up Cozy could work. It might help her understand friendship a lot more if she's around foals. They could also probably serve as a role model for her. Just keep an eye on her, because something tells me our new little one is going to be quite the explorer."
Cozy, meanwhile, saw that the magic strap had finally released her. But as it did she tried to remove her diaper with her hooves. Instead of ripping it off however, the diaper became bigger and poofier, making it harder for her to walk. "HEY! What gives?!" She demanded in a confused tone as her diaper inflated.
"I knew you'd try to remove it, which is why I took the liberty of putting a spell on the diapers," Twilight explained. "If you try to remove it, it gets poofy and harder for you to walk. Only the grown ups can remove it, not you silly filly. And don't even try removing it with scissors, it won't work. I put everything I had into that spell, and from what I read parents used to place that spell on their little ones' diapers all the time, until foals started inflating their diapers to the size of balloons," Then she smiled. "Let's put you down for a nap for now, shall we? You're being quite the fussy foal today, and I think that's because you didn't take your nap. All foals get fussy if they don't take their naps." She picked up Cozy Glow with her magic and carried her over to the crib slowly, making sure her foal didn't fall. Soon, she put her safely in the crib and covered her up with a blanket.
"Oh, I almost forgot!" Twilight realized and rushed out of the room. She quickly came back with a warm bottle of milk and put it in Cozy Glow's hooves so she could drink it. "Drink up little one, it'll help you sleep."
Cozy Glow sighed, there was no other choice here. She couldn't get the diaper off, so she had to obey them, for now at least. It didn't mean she'd completely listen to them, she'd be sure to give them the most uncooperative foal imaginable before long. But for now she was kind of thirsty, so she started drinking her warm milk. Once she'd finished, Twilight picked her up and burped her, then put her back in the crib. "Goodnight sweetheart." She called and she kissed Cozy on the head, then turned off the lights and left the room.
"This is going to be a long and embarrassing stay," Cozy said to herself as her tummy started growling ominously. "Oh please just be hungry, please don't let it be my other business…" She pleaded and tried harder to sleep, though the extra padding on her rump made it difficult.