Basically, its an equestrian for unicorns. A person who rides unicorns. A uniquestrian does all of the same things that a normal equestrian would do, except on a unicorn. A uniquestrian does do certain things that an equestrian obviously cannot do, like riding their unicorn to Alaska, eating butterflies, pooping rainbows, and basically being EPIC.
Guy 1: When I get older, I'm gonna be an equestrian.
Guy 2: Fuck that. I'm gonna be a uniquestrian. They're way more awesome. Plus you get to ride a unicorn.