1. Fit cozy to bottle. With right side out, pin the napkin into a tube shape around the desired bottle, overlapping the edges to fit. Remove bottle.
2. Secure fabric with buttons. Beginning 5 inches down from the top of the tube, secure the edges by sewing 4 buttons, evenly spaced, through both napkin layers.
3. Sew bottom. Turn tube inside out and flatten, keeping overlapped edges centered on the side facing up. To fit bottom of napkin to bottle, fold a 1-inch pleat on each side of tube at bottom edge. Machine-sew across bottom of tube, catching pleats in seam. Turn cozy right side out.
4. Slide the cozy onto the bottle. Tie the ribbon around cozy at neck of bottle.