And just what is "planking" and "capping"?
Capping: On open column ends where there are no stitches to cut the Foam, if left unedited, Foam will extend from these open ends and it will have to be removed by hand. You can either "Cap" the end of a wide satin stitch column by either placing a satin stitch in the opposite direction, adding running stitches inside the open column, or throwing varying stitch lengths toward the center of the column along the instide column edge while keeping the outside-edge straight to cut the Foam and cap the end. Tapering the end is another option.
Planking: Can be done in areas where columns intersect which can result in collapse of the Foam. Vary the stitch length so you don't creat a cut line for the Foam. (illustrations of both of these techniques appear on page 36 of the book, Sulky Secrets to Succesful Stabilizing #900B-11).
Carol Ingram, a premier designer for Sulky, often uses Puffy Foam as a base for designs with fill-in stitches, which adds dimension and allows designs to be used as ornaments or for home-dec projects and they do not need to applied directly to fabric. See Carol's "Quick Ornaments & Accessories" project in the book, Sulky Secrets to Successful Applique #900B-14.