Flocking is a technique used to transform a plain, bare tree into a full and fluffy tree with a frosty or snowy appearance. It involves applying a white, fluffy material to the branches of the tree using a special machine. The result is a tree that looks like it just came from a winter wonderland. Some flocking kits even come with special glitters that add an extra sparkle to the tree. It's a popular way to create a unique and festive look for the holiday season.