Title: Twily & Dusk's 63'd Adventures!

Main characters: The Mane Six, Spike, Trixie.

Genre: Alternate Universe, Comedy, Adventure, Romance(NSFW).

Premise:
Dusk Shine, wanting to get a little alone time to himself, attempts a special teleport spell that will send him to anyplace of his choosing.

Upon performing it, it doesn't seem to work. However, when he gets a good look at Spike and his old pictures he discovers that he's in a world where every ponies gender has been switched, he has switched places with his counterpart: Twilight Sparkle!

Back in his universe, Twilight experiences the same situation.

At first, their both disappointed and worried, however upon realizing that all of their friends are now Stallions/Mares, they realize that they can now relax without any of their friends coming on to them!

They tell Spike/Barb that they were testing a gender swapping spell in order to see life through the opposite gender's eyes, and that the spell will only last a day. When Twilight/Dusk tells his/her friends this however, they believe that Twilight/Dusk is using this spell as a test to see if they would love them even if they were the same gender.

As a result now they must avoid getting flirted with by their friends genderbent counterparts!