Start with a rectangular sheet of paper
Fold it in half lengthwise
Unfold it
Fold the top two corners down to the center crease
Fold the new top edges down to the center crease
Fold the paper in half along the center crease
Fold it in half again to make a smaller strip
Hold the folded paper with the open ends facing you
Pull the top layers outward to form the popper shape
Pinch the middle firmly
Swing your wrist downward quickly to make it pop