Cut the elastic to fit the dog: It should start at the tops of the dog's shoulders and loop around the front legs to fit snugly, like a backpack. Tack elastic into loops, and sew onto underside of black wings. Fold gray felt in half, and align wing template with the folded edge; using the template as a guide, cut out wing shape and unfold. Trim 1/4 inch to 1/2 inch from edges so gray felt is slightly smaller than black felt. Glue gray felt to black felt with fabric glue and a paintbrush. Using the templates as guides, cut out markings from yellow and black felt; glue in place.