I have sewned with minky a lot. I use a dab of Elmer's washable school glue to hold pieces together then sew your seam. It will not shift. Glue will wash out. You don't need a lot. I've backed many with minky also. Again I used Elmer's washable school glue to sandwich the quilt. I have no puckers on the back whatsoever. Give it a try.