1. Start by separating your cookie dough into 6 sections. You need to split the dough into the same number of sections as colors you're using. So if you're using more than 6 colors or fewer than 6 colors, adjust accordingly.
2. Dye your dough into each of the 6 rainbow colors (red, orange, yellow, green, blue, and purple) by adding a little food coloring to the dough, and then kneading it in until the dough is completely dyed. I used gloves for this part to save my hands from being rainbow too.