When you fill a piping bag, place the empty bag, with your desired piping tip, into an empty glass and scoop your icing into the bag. If you do not have piping bags, a plastic bag will work just as well; all you need to do is turn the bag on its side and place the piping tip in the corner of the bag.
When preparing your icing, make a large batch of white icing and then separate into several different containers. Dye each container a different color, this will give your cookies an extra dimension and make the details pop! When dyeing your icings we recommend you use gel food coloring over liquid food coloring, this will give you more control of your icing color and keep the icing from getting runny.