Ruching is a form of stitching and gathering. To ruche a bias tube with zigzag stitches, mark out points at intervals down the length of the ribbon—roughly twice the ribbon width—and connect them with a disappearing ink pen. Hand-or machine-stitch along the line. Then pull the thread ends as you push the fabric to gather it for a loose or tight effect. Arrange the ruffles so that they lie flat after you have secured the thread.