So I want to put cut out gum paste letters on the side of the cake instead of the top (the only way I have done it so far) I use SugarShack's buttercream for my cakes. Is there anything special I need to do to get the letters to stay on and stick? If I am doing dark pink letters and putting them on a white buttercream is the pink from letters going to bleed on to the white buttercream?

Thanks for any help you can give me!

A little tiny bit of water on the back of the letters is all I use to stick any fondant/gumpaste decor to the sides of cakes. I haven't had a problem yet. You do need to be cautious of bleeding, so only use a very small bit of water and don't move the letters.