Here are the how-to's and results:
6. Fold each remaining short end, wrong side together, approx. 1/4" and pin.
7. Now fold the two lengths of ribbon wrong sides together, starting at the short seam. Topstitch down each long side, close to edge. When you get close to the end with the folded ends, repin if necessary to ensure that the folds match up. Stitch to end, backstitching to secure folds. (Leave the short side open.) You should now have a casing with both long sides topstitched and one short seam sewn inside.
Happy Valentine's Day!