^What exactly is a "kidding?" Nobody ever told you what a "kidding" was. You just immediately are taught to say "Just kidding with you" or "Just kidding." "Just kitten" just MAKES MORE SENSE.
person 1:I heard Canada was anexed into the U.S.
person 2:That is the most retarted thing i have ever heard
person 1:Oh, i was JK.
OR
person 1:Oh, i was JK'ing