When I used sanding/crystal sugars on bc, the color bled and made a mess. I want to use it on fondant, any suggestions?

I've used sanding sugar on fondant and haven't had any bleeding issues. The process I follow is to apply a think layer of piping gel where I want the sugar and sprinke the sugar on. Be sure to avoid any condensation as this will most likely cause your sugar to melt/bleed.