how do i get them to stick? i haven't tried yet, but just realized that i have done it in fondant and used extracts or water as the 'glue'. Will i need a 'glue' for them on b/c?

I'm doing vertical stripes on a cake right now with buttercream underneath and I spritzed the buttercream with a tiny bit of water before putting the stripes on. Just don't mess up or it's a pain pulling them off. Frosting comes with! I'm dealing with my re-do right now. Gonna be a long night

A tiny bit of water works, remember" TINY "water and fondant are not friends. You can also use corn syrup A LITTLE BIT, gum glue. Doesn't take much of anything.

I've done them on buttercream many times and I never use anything. I have a baby shower cake that I just made...it's in my pics....that had a lot of vertical stripes. I use the melvira method to smooth my icing, so when I am done adding the stripes I just lightly roll over it again with the roller to smooth everything out. You can do this with your hand and parchment paper or a viva paper towel as well.

Edit-- I forgot that I never uploaded that pic! Either way, every cake I made has buttercream icing and some sort of fondant accent (stripes, etc) and I never use anything. Just make sure you add them right away before the fondant dries out.

Just did this a couple of weeks ago. I always use vanilla. Just brush it on the back of the fondant stripe, down the center and place on the cake. Works perfectly every time!!