When you sew on paper, set your stitch length to more stitches per inch and the paper will be perforated so it tears off easily. Don't tear it off until you are ready to use it. The paper is there to stabilize the odd shapes where there might be bias edges. Keeping the paper on the back until you sew it to your other pieces, you will be able to maintain the shape. If you fold the paper it also aids in removing it.