There is a method for doing this. You sew a strip of fabric right sides together with the quilt top, sewing along the seam alowance of each little jagged edge. Clip your corners and trim the seams, and turn the facing to the back side of the quilt. You will have all the individual corners there, completely filled with batting. You probably want to sew around the edges at that point, maybe not. Turn under the facing and hand stitch to the back. You might even start with a double thickness of facing and then the fold is the part that gets stitched to the back of the quilt. I haven't done this but have seen it done and it looks great. Sorry I don't have more details. You could also do a regular French fold binding, but that would be a LOT of corners.