Karen shows you how to mix your colors and fill your bags. This example uses red blue and black. Begin by mixing blue. Start with royal blue coloring and add it to your frosting and mix it well. Dump the colored frosting into the middle of a sheet of plastic wrap. Roll it up in the plastic wrap, twist the edges, and now you have a little pouch with your frosting. Now take a bag with a coupler, and stick the plastic pouch of frosting in it. Pull it tight and rubber band the top of the bag, then snip the plastic bags tip and attach your tip to the end. Do this with red and black and you'll have made three colors, and only dirtied one bowl, and one spoon.