No particular thing, it developed out of a desire: I wanted to write a long form epic tribute to cumflation as it is by far my favourite kink and I knew I wanted to have something with size difference via horseyness as there is something very raw about that.
I love fantasy and it is the genre I read most by far, I also love magic and fun characterisation and epic adventures. In the end high fantasy + magic as a genre I think was somewhat inevitable though, a centaur has a ton of logistical problem when it comes to bonking that magic made a lot simpler, that and it provided some very clean and believable explanations for things like added stretchiness. [Blob Cookie]