I've honestly never heard any non-American use that term and nobody has ever actually explained it nor have I ever been inclined to look it up so I don't know what the forget.
yeah, honestly i'm thinking it's something to do with ambient oxygenation levels in the bloodstream of the bits, making people think you're "blue", but i really have no idea. also: to anyone saying you wouldn't do it to music, you should probably realize it's incredibly awkward to do it with someone you're not intensely familiar with, in the absolute silence. get some ambience going.