Changing the color of white frosting to orange doesn't take long. All you need is red and yellow food coloring since these two primary colors make orange, which is known as a secondary color. The most effort tinting the icing will take is precisely counting the drops of food coloring you squeeze from each tube -- you can't estimate the number of drops, or the frosting might turn out too yellow or peach-colored.
Squeeze four drops of red food coloring from the bottle into the white frosting you want to color.
Squeeze 12 drops of yellow food coloring into the white icing.
Blend the white icing with a spoon until the red and yellow is completely mixed and the frosting is a uniform orange color. If it looks too yellow, add two more drops of red and mix the frosting again.