Hi,

How do I get Damask effect on the sides of the cake like this picture? I have the stencil but I'm afraid to mess it up. What do people use? Royal icing or those dusts?

http://boards.weddingbee.com/topic/inspirational-cakes
 

AI believe that most people use royal. And practice.

Hmm okay.. and how do I stick the stencil onto the cake so that it doesnt move while applying the royal icing?
 

I do royal on fondant. i've heard of people using buttercream on buttercream (the cake being hard, perhaps an all -butter buttercream), but i haven't done it. 

I have had an assistant (read: husband) hold the stencil in place while I spread the royal, then peel the stencil off.  But I have also been told that you can wipe the back of the stencil with a bit of shorting to make it stick.