When the girls are having a sleepover at Sunset Shimmer's house, Rainbow Dash pulls a prank on Sunset, so that the next day, Pinkie Pie sniffs her butt, which smells like chocolate for some reason. And the next chance she gets, Sunset gives Rainbow a taste of her own medicine.

Contains: Butt sniffing, light butt slapping, and butt licking, with underwear references. Possible olfactophilia, but of pleasant smells rather than the usual sweat, fart, scat, etc. A little different from my usual fetishy stories, but a bit fetishy nonetheless. (Given a lot of the buttplay in the show I'm not sure if it's necessary, but I put a Sex tag on it just to be safe, which I changed to a Fetish tag once it became available).

I got the idea from a movie I saw, along with an episode of, I think Star vs. the Forces of Evil.

Might be a little stretchy, as usual, but mainly done for someone (can't remember who) who said they like this sort of thing (but not farts).