I prefer to use decorating bottles for my flood icing, but I always run the risk of the icing getting low and an air bubble blasting through the tip and ruining my hard work. That said, I find it best to use piping bags, either disposable or reusable, fitted with Wilton tips #2 or #3. You can also use larger tips like a 1A if you're using it for something like a gingerbread house and you need a little more volume in your squeezes.