A rather obvious mockery of "kung fu", meant to discriminate those who can kick your ass, and to tempt them to do so.
"aww, look at the cute fruit head, doing his fung ku! HAHA!"
A phrase clearly stating, "Don't Feed the Bears" this rule is best followed if one cares about his or her puny pathetic life. Otherwise just screw it, feed the friggin' bear.
"Billy! I said not to feed the bears!"
"No! Not buts, this is the last time i get you a fake body part!"