For a 3 tiered wedding cake the bride would like a sparkling trail of some sort going down from her topper diagonally across each tier to the bottom. She had originally wanted some sort of edible gems but she is on a tight budget and to do that many gems would have been too much of an expense. I suggested Sparkling White sugar. What would be the best way to adhere the sugar to the side of a fondant covered cake? I was thinking Royal icing or piping gel. I want to make sure it stays on there and the sugar retains it's shimmer. Any suggestions?
TIA

I think I would go with the piping gel.