Sun by SuperPinkbrony12

The Cutie Mark Crusaders were hardly strangers to unusual ideas for their cutie marks. After all, they’d done a lot of ideas that most ponies wouldn’t think of.

But when they found themselves attempting to earn their babysitting cutie marks, they could hardly imagine that the foal they would be tasked with looking after, would be none other than the regressed Princess of The Sun.

Apparently, a spell cast to make herself younger that backfired, and Princess Celestia was currently stuck in the body and mentality of a two year old. Since Princess Luna needed her new little sister looked after, while she and Twilight searched for a cure, she had reluctantly been persuaded to give Celestia to the CMC.

“Now, pay attention, Tia,” Scootaloo said, addressing the regressed raiser of the sun by the only name she responded to “Here’s what you do with a potty.”

The toddler Celestia watched with interest, as Scootaloo sat her rump on a white training potty. The object looked funny, but she was told it was something ponies her age used quite often.

“You sit down, right here,” Scootaloo instructed, and started to grunt and push “Then you do this!” In a matter of seconds, with a series of farts, Scootaloo released her bladder and her bowels into the training potty.

“Good girl, Scootaloo! That’s how it’s done!” Sweetie Belle cheered, then the smell reached her nostrils “Ew, Scootaloo, what did you have to eat for lunch?!”

“Just some peanut butter and zap apple jam sandwiches with apple juice,” Scootaloo replied, and turned to Princess Celestia “By the way, the farts are worth extra points. It’s how you potty like a big girl!”

“Look, Tia! Look what Scootaloo’s doin’!” Apple Bloom encouraged “Do it just like her, and you’re a big girl too!”

The regressed Princess of The Sun giggled “Scootapoot!” she teased, and waited impatiently for her chance to use a training potty. In the process, she unintentionally released a rather gassy fart.

“Ew! That really, really stinks!” Scootaloo complained.

Sweetie Belle, despite plugging her nose, chuckled at the statement “Well, Scootaloo, she learned from the best. Speaking of which, you need to let Tia have a turn.”

“But I haven’t even tinkled yet!” Scootaloo protested, but did as she was told.

“I think you’ve demonstrated how to use this thing quite profoundly,” Apple Bloom replied, as she grabbed the training potty “I’ll be right back, I gotta go empty this out in the outhouse.”

“Okay, Tia, the potty’s all nice and clean for you!” Apple Bloom called, as she trotted back into the clubhouse, placing the recently cleaned plastic bowl on the floor of the clubhouse.

Princess Celestia giggled, raced over to the potty, and sat down on it without hesitation.

“Might wanna hold your breath girls,” Scootaloo gulped, plugging her nose “I get the feeling this is gonna get really stinky!”