You will need powdered sugar, milk, corn syrup, vanilla, and food coloring.
Mix the powdered sugar and half the milk together.
Mix in the corn syrup and vanilla extract.
Add milk, a little at a a time, until the desired consistency is reached.
Use gel food coloring to create your desired colors of icing.
Decorate your cookies with the icing.
Add sprinkles and allow the icing to dry. Enjoy your cookies!