Author's Note

This chapter does contain any diaper wearing or sexual themes. However, this will change soon in the story, so be warned.
Also, any feedback will be greatly appreciated. Constructive criticsm on grammer, text, characterisation will be welcome.
This is my first time writing fanfiction, so I need all the pointers I can get.
And thank you for reading.

1. How it all started

Chapter 1:

How it all started

Celestia yawned. It was the yawn of a mare who had spent the whole day trying to fix the mistakes somepony else had made. The fact that the pony who had made those mistakes was her sister made no difference. She was Celestia, princess of Equestria, a pony who was the epitome of responsibility, caring and a role model for thousands of fillies and colts, along their parents and their parent’s parents. It would just help if she hadn’t spent the whole of last night fighting of Starlight Glimmer’s evil interpretations of her and her sister.

Flicking though the last pages of a document, she signed her name at the bottom, then with a burst of will, a golden seal appeared beside her name, proving its authenticity. Her last piece of paperwork done for the day she leant back in her chair, ready for a well-earned two-minute bre- >POP< A dark blue alicorn appeared in front of Celestia in a flash of arcane light.

“Arghhh!” Celestia let out a high-pitched scream but quickly stifled it with her hoof. “Luna, how many times do I have to ask you not to teleport right in front of my face?”

“Tia, stop being such baby, it wasn’t that scary.” Luna said with large grin of her face.

“I was not scared, merely startled.” Replied the larger alicorn, trying to regain her composure, “Anyway, why did come here, you know it’s half an hour until it’s time to raise the moon?”

“Aww, was little Celly afraid of the big bad blue pony?”

“I wasn’t scared I-”

“Do you want me to check under the bed to make sure that the boogymonster isn’t there?”

“Knock it off.” Celestia gave her sister a playful shove. “Getting back to the point, why did you come down so early?”

“I wanted to see how you handled the um, incident of the school field trip. I do hope those fillies manage to go on their trip, I will not be able to forgive myself if they cannot go because of me, besides that dream was horrible.”

“Now who’s the baby? The princess of dreams being scared of a little nightmare, please.” Celestia relished the opportunity for the little jab at her sister, it was not her who had started the little argument.

“I’m not the one who had a night light shaped like the sun until Starswirl had to help you get over your fear of the dark.”

“I wasn’t the one who wet themselves when she first saw a manticore.”

“Well I didn-”

“Hang on, hang on!” Celestia put a large hoof over her sister’s muzzle, “Let’s not fight, this is exactly why Starlight was sent here, to stop this petty squabbling.” Lowering her hoof, she continued, “What if we had a little competition, to prove who is the biggest foal out of us?”

Luna gave out a little chuckle, “Well we both know who would win that competition.”

“And who would that be?”

“Me of course.” Both the sisters laughed at this. Between the two of them, Luna was known to have the most competitive nature.

Stifling the last of her giggles, Celestia spoke, “So, do you have any idea what to do for this competition?” Both the alicorns sat in silence for about twenty seconds before-

“I’ve got it!” A blue hoof shot into the air. Blushing slightly at her outburst, Luna continued, “We could both wear diapers.” This was not what Celestia was expecting.

“Really Luna.” She gave her sister a slow clap, “Stop joking around and help me think of an idea.”

“I’m not joking.” Celestia gave her a raised eyebrow, “Just listen to the idea okay.”

“I’m listening.” Came the slightly sarcastic response.

Not put off by her sister’s tone, Luna continued, “Well what’s the most foalish thing you can do? It’s wearing a diaper.”

“I don’t see how-” Now it was Luna’s turn to cover her sisters mouth.

“Let me finish. Now the only thing more foalish than wearing a diaper, is being changed out of your diaper. What I propose is that the one of us that manages to stay in a diaper the longest without being changed is the victor, and when the loser gives up, they have to ask the other pony to change their diaper.”

Celestia laughed, “That doesn’t sound so hard, I would win that competition in a-”

“And when I said stay in a diaper, I mean no taking of your diaper what so ever, under no circumstances.”

Realisation dawned of Celestia, “Augh, no Luna, that’s disgusting.”

“You said you wanted a competition.”

“Well I didn’t think that such a competition would include me defecating in my undergarments.”

“Come on Tia, it won’t be that bad. Or, are you too much of a foal for this challenge? Is little baby Celly scared of a little diaper? Do you need to put a little dummy in your mout-”

“Okay, I’ll do it.”

With those words, although she did not yet know it, Celestia had signed herself up for a very, very interesting week.

“Well then, it’s settled, diapers will be our challenge. Tonight I will come up with the rest of the details and give them to you tomorrow morning while you get some well needed, well-deserved rest.” With that, Luna’s horn began to glow, signalling a teleport spell being cast.

“Hang on wait!” Celestia tapped Luna on the nose, “To answer your previous question, yes, I was able to raise enough money for those school fillies, under your name as well.”

“Thank you Celestia, that, that really means a lot to me.” Luna pulled her sister into a quick hug, then teleported with a flash of blue light, leaving nothing but a small wisp of smoke and a warmth in her sister’s heart.

“Luna,” Celestia thought,“I am so glad you back.”

With that happy thought, Celestia finalist her paperwork, double checking the signatures and making sure that all the documents were in the right place. Lifting her checklist up, she marked of the second-to-last box. The last box read “Lower the sun,” and in bold print, “and make sure that Luna raises the moon.”

Starting up, Celestia looked at the clock, “Luna!” she shouted, and quickly teleported away in a flash of golden light.