1

Make sure that you have the person's undivided attention. This move takes a bit of time to pull off, and you want to make sure to get the full effect.

Hold your fist out in front of you, knuckles facing the offender – but do not raise your middle finger yet. Then, make a fist with the other hand, and crank it in circles next to the first hand as though you are winding up an old-timey jack-in-the-box toy. As you crank, hum "Pop Goes the Weasel," the tune traditionally associated with jack-in-the-boxes. Hum and crank faster and faster as you approach the end of the tune. Then, at the final "Pop" of the "Pop Goes the Weasel" tune, extend your middle finger as though it is the jack popping out of the box. Finish humming the tune while flipping the person off.