A new term used to describe Filipino people. It is not really offensive unless they take it to be. It contains two parts, the first being "Flap" which can be considered the 'other side' of "Flip" (Flip being a regular, shorter way to call a Filipino person), and the second being Jack, which is well, just a normal way to address ANYONE really...
So why does Flap Jack apply so well? The color of flap jacks, or more commonly known as pancakes, comes close to the color of someone originating from/has roots in the Philippines.
"Dude... STOP CALLING ME THAT."
-"You rather me call you Asian?"
"NO, DON'T CALL ME ANYTHING!"
-"Not even Flip?"
"NO- well.. fine, Flip is alright..."
-"Flip - Flap, FLAP JACK!"