Celestia and Luna married the mane six, now they have a harem and a honeymoon to deal with. In all honesty, happily ever after isn't all it's cracked up to be. At least there'll be room for orgies.
Twilight and Fluttershy have been friends ever since the defeat of Nightmare Moon. Not long after Twilight's ascension, Fluttershy decides she wants more.
The Cutie Map summons Luna on her first friendship mission, and she'll be going with her girlfriend, Fluttershy. The only hitch is that it seems to be sending them to another world entirely. Some place called... Hell, was it?
Have you ever gotten so drunk you forgot you offered the princesses' hoof in marriage to whoever brought your sister back? And how many 'es' there are in 'Princess'?