I am going to put a black damask pattern on a white buttercream cake with stencils. What's the best way to do that without making a mess of everything?
Stenciling on buttercream is really hard, and buttercream can/will melt your royal icing if that is what you were planning on using. You should probably do a search because there have been other threads with really good advice on here before. I'm not much more help then that.
I also would not risk it with black, it can bleed, run and ruin your buttercream.