The big mission to infiltrate the Canterlot archives is stopped short when Pinkie Pie reveals she forgot to pee before getting into her skin-tight stealth outfit. (Takes place during episode 20 of season 2, "It's About Time")

Warning: Mature rated fic, contains descriptions of urination and pony/pony-dragon sexuality. (I apologize for not putting this warning sooner, I seem to have gained a lot of thumbs down due to shock).