Fit the decorating bag with tip 16 and fill 1/2 full with medium consistency icing. Hold the bag at a 45° angle at 3:00.(9:00) with tip lightly touching the surface.
Steadily squeeze and move your hand in a tight up and down motion as you move toward the right (left).
Continue piping up and down with steady pressure. To end, stop pressure and pull tip away. For more elongated zigzags, move your hand to the desired height while maintaining a steady pressure. For a more relaxed look, just increase the width as you move the bag along.
Repeat as you move in a straight line with consistent up and down motion.