Up until now I have let my fondant decorations dry and then pushed them into the buttercream. Really don't like this affect though. Tonight I attached them with piping gel, like it better but sure hope it sticks long term. In the next couple weeks I will be wrapping a fondant ribbon around the bottom of my buttercream covered tiers and am very nervous about this. How do I go about attaching the ribbon? Do most of you attach them on the layers before stacking them? I'm just worried that I'm going to ruin the buttercream finish. I really appreciate any suggestions you can give.

i just brush a small amount of water or corn syrup to the back of my fondant pieces before sticking them on the cake. I haven't had any problems yet. Just don't use too much water or the colors will run.