I am guessing if I use thinned fondant os something like it it will pass thru the ribbon...
Ideas?
Thanks!

I use edible glue or RI to stick ribbons on to cake.

I won't use fabric ribbon on cake. (Not food safe.) I do use fondant ribbon, however.

When I did my sons wedding cake I just wrapped it around put a little buttercream between cake and ribbon and a little between the two ends of the ribbon, it held just fine and came off easily when it was time to cut the cake.

I just wrap it around and adhere the back ends together with BC. I have never had a problem.

I use vodka.. a little for me and then some for the cake. If the fondant is just a little bit wet it sticks well then some bc or ri to stick to itself.