Can someone please tell me the best way to get MMF to stick to a buttercreamed cake. I don't mean a whole layer to cover the cake, just pieces. I tried to make a book cake and trying to stick the white fondant around the book for pages was a pain in the neck! It keep peeling off at the top. The cake was in the fridge all night and by the time I started working with the fondant the icing was becoming soft. Also, how much icing do I need to put under fondant? I have noticed that I have some lumps and it maybe to much. I want enough so when people eat it they can have some icing on the edges, because most people peel off the fondant.
Water. Just brush the back of the fondant piece with water.
I don't know what kind of buttercream you are using, but it shouldn't get soft if it's American BC at room temperature or less than 85-90 degrees. You don't need to refrigerate a BC cake unless you're using perishable fillings. Perhaps your cake was sweating after removing from the fridge which made it too wet for the fondant to stick.
The recipe I use calls for 3-4 cups p/s, vanilla, butter, salt, and milk that's it. It's actually really good. I mean it doesn't get soft and melt...it's like the can frosting but thicker. I thought the only way to get icing to crust was to refrigerate it...lol sorry I am really new to this.