I am going to have a bunch of kids at my house this weekend and would like them to decorate chritmas cookies. I am going to make sugar and gingerbread in different shapes. but what do I make to decorate them with? Royal Icing? Do I just color it different shades and put into bags to pipe onto cookies? How far in advance can I make the icing? Thought I'd get an assortment of sprinkles, etc.. too. Any suggestions would be great. Thanks!