When recreating Cookie Monster's iconic fur using piping techniques, one piping tip that works well is an open star tip, specifically a #17 or #18 size. These tips create textured lines that can resemble fur when piped close together in various shades of blue icing or frosting across the surface of a cookie monster-themed dessert. As you pipe with an open star tip, pull upwards gently while releasing pressure on your pastry bag for each line to create a more realistic fur effect. Experimenting with different levels of pressure and spacing between lines can also help achieve different textures for Cookie Monster's fur-like appearance