how do you secure ribbon on a fondant covered cake?

If your using narrow ribbon, soak it in water, run it through your fingers to squeeze all the water out and then just wrap it around the cake, the dampness will hold it on. A wider ribbon I would use touches of royal icing.

This is what my cake deco teacher suggested:

* royal icing
* tylose mixed with water to make a glue
* egg white

I've used floral pins (they are really long and have a ball at the tip) to secure ribbons. Of course, you need to let your customers know about this.

I've also read that people have cut a length of wax paper to match the size of the ribbon to protect the cake. Sometimes colors of the ribbon may bleed into the cake, but this is more of a concern for cakes that are just frosted with icings.

HTH!
Mirjana