My mother did this when me and my 10 brothers and sisters were growing up and we loved it. Lucky for my kids, we recently attended a surprise birthday party for my sister and my other sister made too much frosting and sent me home with a bunch. (woops!! I may have been the one that influenced her to double her recipe. Not on purpose, I promise!)
But when you have left over frosting and don't want it to go to waste, you can make delicious and sweet snacks or sides in the lunch box by making a Graham Sandwich. Frosting too soft? Then use it as a dip with Graham Snack Stix.