5 c confectioner's sugar
3 egg whites (may be substituted with meringue powder if you can't have raw eggs)
In a large bowl, mix egg whites until foamy. Add confectioner's sugar till completely combined. Slowly add water and mix until a ribbon-like consistency is formed. For a thicker consistency just add more sugar. A thicker consistency is used for outlining or adding detail. Thinner consistency is needed for flooding the icing on the cookie. Place icing in a ziploc bag with the corner barely snipped.
Outline cookie with icing. Partially fill in then spread with toothpick to flood icing. The icing will harden quickly, creating a smooth surface. To create a tie-dye effect, after flooding the icing (before it dries) make horizontal stripes with a different color. Starting at the top, drag a toothpick through the icing. Make plenty of cookies so you can experiment until you get the hang of it. To make hearts, make polka dots then drag a toothpick through it.