Image imported from derpibooru 
Original Description:
 
It was opposite day (or night). (alt version without diaper here >>2875424)
 
Cheerilee was on a trip to Manehatten with her class. Scootaloo hadn’t wanted to come originally due to a bedwetting problem which required her to wear some “special undies” to bed. Her friends of course knew about it, but she was too afraid of anypony else finding out.
 
Cheerilee had thought about it and found out that it was easy to arrange the rooms so that one of the students would have to share a room with her. Problem solved! The hotel was even so accomodating to put a plastic liner under the sheets in case of any spills.
 
Everything was going great until around 3:30 AM, when she woke up to Scootaloo gently nudging her awake. It seemed that thinking about it so much had brought her own old tendencies back…
 
At least Scootaloo didn’t seem to mind - she even told Cheerilee that she could tell the hotel that it was Scootaloo, so she’d be spared the embarassment when she went down to get new sheets. Not that anypony would believe that a pegasus filly had made the earth pony mare sized lake they were dealing with…
 
Clean version here  
>>2874769t