I know that vodka can be used to thin airbrush color, but I'm wondering if it's okay to use on buttercream. I'm making my son's birthday cake and really don't want to be explaining myself to other parents. Thanks for any help.

It will evaporate, so don't worry about it too much. If you leave a container of thinned-out color with vodka in it on the counter, you'll see that the vodka evaporates, and that might make you feel better.

You won't have a bunch of drunk kids on your hands, don't worry

Thankyou! I've heard it evaporates, but wasn't sure if that applied only to fondant...anyway thanks for calming my fears.

As was said, it will evaporate and it isn't like you are going to be using a whole bottle on a cake. Chances are you won't even use a whole shot for the whole cake. Don't forget that your extracts have alcohol in them. So your can't isn't totally alcohol free as is.