You can tie it instead of quilting it or try hand quilting it. Your other option is to get it all laid out & pin basted, then try to stitch in the ditch with your sewing machine--stitch next to the seam lines of blocks on the side where you haven't pressed over the seam. You could also drop your feed dogs (if you can do that on a FW), make a puddle around your needle by rolling up the edges of the quilt and clipping it somehow if it's very big and start free motion quilting.