It wasn’t the freshest car ride for Rarity. She farted so much in there the whole cabin really stinks. And Rarity is known for having the biggest & stinkiest farts of the girls these days.

Done by request. Sorry for the poor quality and narrow crop, the requestor found the picture like that and it didn't say which episode this was from so I couldn't find a higher quality screenshot with more room for the fart text.