I forget which year... maybe it was 1992-1/2 when a young child uttered the words for the first time while staring fondly at a familiar pair of moobs. One school of thought has extolled the idea that it means
"Dude, where are your white socks" while other proponents insist it actually means
"Hey there Mr. Moobs, I want another bacon smoothie".
Regardless of its origins It has been in constant use ever since.