I've never had any luck with anything but a straight stitch or sinple zig zag on fleece. When you do a decorative stitch, the feed dogs need to grip the fabric and move it in weird directions to achieve the pattern. If you try fancy stitches on fleece, especially a sandwich with fleece on the bottom, the feed dogs have a hard time gripping the fabric (with all that nap). I don't think that the slider sheet will make any difference. It's not that the quilt is dragging, it's that the feet can't get a grip. The only thing I can think of is to use water soluable stabelizer under the fleece. Between the feed dogs and the fleece. Might need to baste it in place first. Try on a swatch.