How Do You Flood Royal Icing?
Flood Royal Icing is made by thinning down the regular royal icing consistency with water or lemon juice until it is runny enough to be easily spreadable but thick enough to hold its shape and not run off the edges of your cookies. Once you have achieved the desired consistency of the icing, you can then use it to fill in the baked cookies with a small offset spatula or piping bag. After applying the icing, allow it to dry and harden before adding any additional decorations or designs on top.