"What is Gachimuchi?" according to Rev (short version)

Gachimuchi videos are basically the Japanese equivalent of YouTube Poop, known as MAD videos. These videos are fanmade by the denizens of Nico Nico Douga (a.k.a. Japanese YouTube)and are based off of homosexual pornographic films starring Billy Herrington, a leading figure in this trend since it was originally the films he starred in that got the attention.
In the original films the actor(s) would sputter lines that could/would sound like words in Japanese. Take for example Billy, the 'mascot' of these films. In one scene he says, "You got me mad now." The Japanese, limited in the English language (no offense intended), hear this as "Yugamineena" (say them both aloud, they do sound alike).

Yugamineena, being an entirely different set of words (it means "You are not distorted" by the way), would provide entertainment for the denizens of Nico Nico. One thing led to another, and now you have this trend.

(Longer, more detailed version coming soon!)