Beat together the butter and extracts. Start adding in the powdered sugar a little at a time, beating after each addition until you get the desired texture. (if you add too much sugar, a little milk can be added)
If desired, add food coloring and blend well. Split frosting into different bowls to make a variety of colors, or just keep it a clean white.
Apply how you would like to, either with a spatula or a piping bag. If you don't have a piping bag, but would like the effect, clip a small corner off a ziploc bag to use as a piping bag. Don't use generic bags for this, though, as it could burst open at the seam.