Cheating the Cycle of Life- A Padded Pony Collab

Celestia groaned mentally, rubbing her stomach. She looked at her marefriend and former student, Twilight Sparkle, who was tapping a glass of sparkling cider, an empty plate pushed to the side. Her sister was absentmindedly alternating between taking sips of some of the older vintaged wine, and playing a round of Ponymon. Celestia looked at her own finished meal, including a few extra plates where some large cakes once laid on.

Curse my love of cake. Celestia thought. Her bowels were aching for release.

After a rather long drawn out and mostly dull tax meeting, the three royal mares had decided to take dinner for themselves, privately, in one of the terraces. Little did Celestia know what was in her drink. Luna and Celestia, for as long as either could remember, had been in part of a prank war for as long as they had lived, always seeking to improve on their pranks. In response to Celestia replacing the standard bucket-of-water-over-door trick, replacing the water with some slime and frosting, Luna had decided to slip a rather strong laxative in her sister’s drink.

Celestia smiled, taking a sip of her tea. The sugar and warm drink eased her throat. “This truly is wo-” Celestia was cut in mid sentence by a rather large, wet fart. She tried to clench her plot muscles, to no avail. With a fierce blush on her cheeks, her expression like that of a deer caught in the headlights, her tail raised.

A crackling noise echoed around the chamber as the Princess of the Sun began defecating onto her seat, moaning at the relief she felt. Twilight stared at the growing pile, her wings erect, stiff enough you could use them as a crowbar to crack open a safe.

Celestia stopped after two minutes, half embarrassed, half aroused.

Luna chuckled.

“It seems Celly, that being late to be potty trained has come back to bite you in the rump, and you know what mom and dad always did when we had accidents.” She levitated over a diaper with Celestia’s Cutie Mark printed on the front and back. “Now, unless a certain mare would like to c-”

The manure was gone in a flash, and a sheepish look was on Twilight’s face, as she gulped.

“Well, now, lets get widdle Celly into her diapee.” She teased.

As the thick garment was wrapped around her, Celestia already began plotting her revenge....

...And how to get out of this diaper so she could buck the living daylights out of her marefriend, possibly shattering a few windows with how loud her screams would be.