Also one day in advance, ice cookies.
Prepare Color Flow icing following recipe instructions. Reserve 4 cups icing for later step.
Prepare decorating bag with tip 3 and ¼ cup full-strength Color Flow icing; outline cookies. Let set, about 15 to 20 minutes. Thin remaining icing to drop count of 10.
Prepare decorating bag with thinned icing; cut ¼ in. hole in tip. Flow in cookies. Let dry overnight, or 8 to 10 hours.