some years ago on sewing with nancy, she took a piece of fabric, somewhat larger than you think you may need. Wet the fabric, wring it out and twist, twist, twist untill it rolls back on itself. Secure with rubberbands, string, or something. Put in the dryer to dry. When dry, take it out, do not smooth too much.Use iron on interfacing to the wrong side. You will have close to the same effect.