Can't be done the paint will not stick to the mask and if it dose as soon as the mask bends the paint will chip and crack and peal off this is what sin told me it has to be on hard flat surface.
I don't know if this is ture or not, but I heard you can mix some type of liquid rubber stuff with the paint and it will flex and won't chip or crack. I ready about it in a form post at PBC, so I don't know for sure. Maybe someone can check into that.