Fluttershy is gassier than she seems, but enjoys it as long as no one is around. When she accidentally farts during the school play, Rarity rushes to comfort her, revealing that she, too, farts more often than most. They spend the night together, deciding they no longer need to hold it in in front of each other.
Contains: Farts, with some olfactophilia and buttplay.
My original draft had wetting in it, but due to people finding them funny as well, my fart stories are more popular here than my wetting stories, and they just don't go well together for most (I put a wetting-only version on an omorashi site). Also, as usual, quality might be lower, and scenarios stretchy, and don't take too seriously.
I put an Alt. Universe tag on it to show I don't think they fart any more than the average human in canon.