Rarity confess to Twilight Sparkle what really happened in the desert when she was alone with Pinkie Pie. It involved a stream of cool water, wet manes and holding their breaths a lot.
(Author note: Done in 65 minutes for the SextyMinutes tumblr. It doesn´t really has that much of sex. And I couldn´t find a proper RariPie picture. By the way, I loooove wet manes!)