After baking sugar cookie sticks and letting cool, pipe on white icing. I prefer royal icing, but you can also pop white canned frosting in the microwave for about 10 seconds to make it a flooding consistency.
Once white frosting is set, distribute leftover icing (and more, if needed) into 3 small bowls. Use food coloring to dye icing the color you want the dots. Place icing in a piping bag and pipe dots in 3 columns, switching colors every 3 rows until you have 3 blocks of colors.