I am making a 5 tiered square wedding cake. The majority of it will be covered in fondant with two of the tiers covered in Wilton white sparkling sugar sprinkles. I'm debating...do I apply to fondant or buttercream. If fondant, what do you suggest as an adhesive. 

Going for what will look best or what what you've had luck with in the past. 

Thank you!

fondant, painted with gel, sprinkles