Its strange that the pony tail movement has ever had any real weight behind it in the hair fashion scene. Because on a pony the place they have the tail is the ass. So its kind of like the myriad girls and some boys who have it are saying, "Well, I thought I could make myself prettier by making the back of my head look like the back of a large, stupid mammal. A mammal with no sphincter, mind you."
Its weird.
A friend proposed the theory that everyone who has a pony tail secretly sees themself as a horse's ass. I think that's nonsense.
It's a pony's ass.