I used Minky from JoAnn for the backing for my granddaughter's drag aroung quilt. I brought it around to the front and mitered the corners. It looked like it would ripple when I sewed down the edge so I glued it with Elmers. When dry, I stitched it with a serpentine stitch. Jenny Doan an a nice video on this.
https://www.youtube.com/watch?v=OOZqOuBPIqs