searching for a story · 2:38am Feb 25th, 2017
It's about a human who gets contacted by Twilight (Discord in disguise). He accepts the contract and become Twilight's (the real one this time) sex toy. the human (I think his name is Alex, not sure) is sent to Equestria and turned into a extremely feminine stallion. Twilight hides him from her friends for reasons that I can't remember.
If you know the fic, thank you for linking it in this blog or even just mentioning it's name so I can search for it.