First of six to be made… This will take a while. Poor Celestia is locked out the bathroom by Luna.
“Lulu, please let me in!” Celestia whined as she gently struck the door with a hoof. On her back side was a large, fluffy, night-printed diaper. With the moons and stars, the diaper screamed that it belonged to Luna.
“Nope.” the moon princess replied from behind the door.
Celestia’s need grew a bit more as her body fought against her.
“I said I was sorry for taking!” Her voice more high pitched and whiny, much like a young foal’s.
“You’ve got a potty on. Use it.”
Celestia gave a soft whine as she clawed at the door.
“If it’s on, you won’t be wasting it, sister.” Luna stated very sternly, almost motherly.