Smolder and Ember were, for obvious friendship reasons, made to wear diapers. Neither of them were particularly fond of this idea, but as they were in Equestria to learn about friendship anyway, they figured they should just wear them anyway. Ember had been in her diaper for a while since she'd been padded by Twilight since she arrived at noon, but Smolder'd had an opportunity to used the bathroom before getting diapered, so she knew it would be a while till she needed to use hers. A couple hours into it, Smolder looked over at Ember and saw her holding her stomach and trying as hard as she could to keep the inevitable from happening. Smolder said, "Whatsa matter, Dragon Lord? Gotta use your diapees?"

"Shut up!" shouted Ember as she struggled to hold it in.

"I bet you're going to use your diaper in the next ten minutes," said Smolder.

"If you don't be quiet, I'm going to flame that smile off your precious little face!"

Smolder chortled and said, "Will that be before or after your diaper change?"

Ember growled and was about to reply when suddenly she straightened up and felt her diaper get warmer and heavier. And before the wetness had fully absorbed into the padding, Smolder doubled over and roared with laughter. Ember looked up at her with fire in her eyes and said, "Now listen here, you little $#!%! If you don't stop laughing right now you're going to be missing a face!"

"Oh-ho yeah," said Smolder, "big, scary Diaper Lord's gonna make me stop laughing. Whatcha gonna do, squish your messy diaper on my face?"

Twilight later came back from looking for foal toys to find the entire room blackened with soot and her table's centerpiece ablaze...