How do I "glue" a strip of colored fondant to the side of my cake?
Is the cake covered in something?
Or you are trying to stock fondant onto uncovered cake?
Lick it, and stick it on.
Kidding. Wet the back with a damp paper towel, moisten your fingers with water, and rub it on, use piping gel, a smear of Crisco, many many choices.
I will putting this strip on the cake covered with buttercream icing. Thanks for your help. :-)
Aif the buttercream icing is not the "crusting kind", it will stick to the buttercream on it's own.
Otherwise, use AZCouture's suggestions.