Back in the old days (lol about 5-6 years ago), it was because of Degeneration X from the WWE saying it and doing their hand gestures. "If you're not down with that, I've got two words for you" and all that. Of course, there is also the South Park reason. South Park did and still does a lot of "suck it/my balls" jokes, so alot of people got it from there as well. I' m sure that the term has been around longer than that, but those are the two best references that this generation hears that stuff from,and imitates. All it is is a derogatory term used to make the person on the receiving end embarrassed or humiliated by suggesting that they are a homosexual and usually do that kind of thing. Also, it can be used just to cause a fight purposely, if the user is in a particularly bad mood and wants to take their aggression out on someone, by saying the term, they hope to cause a fight to relieve stress.
Of course, the only real reason anyone should want to use that expression is when they are with a woman and they want that to actually be done to them lol.
