I use mole skin. You will find it with the Dr. Scholl's foot supplies. It comes in a good sized rectangular shape and is about a quarter inch thick. Just cut a piece off while the backing paper is on, take the paper off and lay it on your mark. It sticks well and doesn't let the fabric wear into it for many many uses. Use the uncut edge as the side toward your fabric, or use a rotary cutter to be sure you have a straight edge.