You have to be really careful with the Bias. If there is stretch, it's important to pin the border making sure not to stretch the fabric and sew leaving the needle until you reach it on the machine. Slow and easy. It's also important that you PRESS (just setting the iron on the seam with fabric right-side up) don't iron it moving the iron. Then turn over to wrong side of fabric and press the seam again. Work out to the edge. DO NOT go back and forth running the iron parallel to the seam. Hope this helps.
Originally Posted by Candace
Are you stretching the fabric as you're sewing? I would use a cotton batting and when you quilt it and shrink it up, I think you'll like it better.