I've seen a few people who have done this. What do I do? My only thought is to refrigerate or even freeze the iced cake 1st.

Has anyone done it?? Is it hard to do??

Here check this out:
http://cakecentral.com/articles/137/how-to-stencil-on-buttercream-video

Thanks, that helps a lot. I think I will try it out for my mom's B-day cake

You definitely want to give your cake time to crust. Putting it in the refridgerator for 1/2 hr. is even better. The stenciling is pretty simple. I have done a couple. I use an icing that is a little thinner than what I used to ice the cake with. When I did it, it was tone on tone. So what I stenciled with was just a little deeper ivory than the iced cake. I held the stencil gently against the side of the cake and using a small palette knife I carefully iced over the stencil. Clean off the palette knife and go back over the stencil taking off any excess icing. Carefully peel the stencil away. Clean the stencil and move to the next area matching your pattern.

HTH.
Jean

Here is the finished result. It was super easy and I love it!!!!

You did a great job. It looks perfect.

Now I just need to find bigger stencils so I can cover the entire side of the cake

Wow, that's gorgeous!!! Now, I need to find time to give it a try -- hope mine turns out 1/2 as great as yours!

Oh, and one question: How did you hold the stencil up to the side of the cake as you smoothed on the buttercream? Is there a way to attach it so that your hands will be free?

do you have a tilting turntable or did you do that cake just flat on the counter? It seems it might be easier if it was at a tilt.

Not a tilting turntable, just had my husband hold it up for me. I don't know what I would have done without the 2nd person.