Get a medium-weight fabric that has a shiny side to it and join two pieces together. Consider the shiny side as the 'right' side. Then using your pinking shears (these are the fabric scissors that cut in zig zags so the fabric does not fray) cut along the seam edges on the 'wrong' side of the fabric. Run your fingers along the seam between the two pieces of zig-zagged fabric (before you press the seam open with an iron as seen in the photo). It's a lovely sensation!