Training to perfectly control one’s gag reflex? Well I’ll tell you this: it didn’t begin with a sword.

Go on...

You'd think it'd be more popular with women...

I would venture to guess a copious amount of drugs, boredom and wanting to show off or impress.

Sticks have been around very long time, swords millennia. And then we can think maybe some eat competition as well. Ending up with someone eating their sword or or just showing off by pushing it down the throat is probably inevitable.