Creating a rainbow effect in a glass with different-colored cordials requires a special pouring technique. Simply pour each liqueur slowly over an inverted teaspoon (rounded side up) into a glass. Start with the heaviest liqueur first. (Recipes will give proper order.) Pour slowly. The rounded surface of the spoon will spread each liqueur over the one beneath without mixing them. You can accomplish the same trick using a glass rod. Pour slowly down the rod
Begin by pouring the heaviest ingredient into a glass normally, then pour the next ingredient over the back of an upside-down spoon slowly into the glass. The spoon tip should almost touch the current fluid level, but should be always kept above it. Each layer should be at least 10 degrees of proof higher than the previous layer. Though as many liqueurs as desired can be layered on top of one another, the majority of layered shots only contain three to five different layers.