Accordion-fold the swag. Lay the swag out flat on a clean surface. Measure 3 inches of the width, and fold over. Fold the material back on itself for a second 3 inch fold. Repeat this action until the entire piece is accordion-folded. It should be a long narrow strip now.
Pin the folds in place. Place sewing pins through the swag every 8 to 10 inches to hold the accordion folds together.
Mark the center of the swag with masking tape. Measure the length. Find the center, and place a piece of tape on the swag.
Hang the curtain rod according to the manufacturer's directions.
Place the center of the swag at the center of the curtain rod. Hold the swag so the center is at the front. Loosely lay each side over the top of the curtain rod to hang down behind the rod. Remove the pins from the section in front of the curtain rod, letting it unfold and hang down.
Adjust the swag to the desired form. Wrap the ends around the curtain rod once or even twice, and then remove all the sewing pins.