In a small bowl, stir together flour, cream of tartar, salt, Kool-Aid, and glitter, if desired. Pour water into a small saucepan and bring to a boil. Remove from burner and quickly put several drops of food coloring and essential oils if using into the water. Pour into flour mixture, stir, and knead until completely combined. Let cool before letting kids play with it. Lasts for several months if kept in an airtight container or bag.