You know what would be really funny if in Season 4 or 5 Twilight messed up a spell and caused Rarity's voice to come out of her mouth, Twilight's voice to come out of Rarity's mouth, Rainbow Dash's voice comes out of Applejack's voice, Applejack's voice comes out of Rainbow Dash's mouth, Pinkie Pie's voice comes out of Fluttershy's mouth and Fluttershy's voice comes out of Pinkie Pie's mouth?
Season 3 finale pretty much had a "kind of" body swap thing going on, so i doubt it. There would barely be any difference
So who wants to talk more about this idea by the way it's not the same thing as the cutie mark swap it's different.
The only way I could imagine Fluttershy doing something like that is if instead of swapping bodies and voices with Pinkie Pie like I mentioned she switched bodies and voices with Rainbow Dash.