One of Disco’s favourite jokes to tell; the fact that noone is laughing just means that they have poor taste in comedy.

Anyway, Disco’d favourite flying-position is upside down. This shouldn’t really be possible, since pegasi cannot fly properly upside down, much less hover like this in place. Hovering, flying forwards, flying backwards, sure, but not usually upside down. 

But Disco isn’t quite like most pegasi, or even like most pegasi-mules; most people chalk this up to Pinkie’s son being Pinkie’s son. One of the ways this manifests in how strangely his wings are shaped, having a very short “arm” (undersized humerus, radius and ulna) and a incredibly flexible wing shoulder. This wasn’t visible when he was a foal, during which he could fly normally, but grew more and more pronounced as he reached adulthood. He has to flap his wings like a hummingbird just to get of the ground now, and he’ll never win any races. 

This would be a pretty crummy situation to be in, but Disco decided he would just have to invent a new way to fly. Taking inspiration from already being described as a humingbird, he consluted with Fluttershy and figured out a way to use his wing-shape and flexibility to literally fly and hover like a one. So now he can annoy Kinyume upside down as well as rightside up!

Kinyume doesn’t really care, rightside up or upside down, he’s still just a big doof who hasn’t paid his part of the rent yet this month.