Flocking an artificial Christmas tree involves applying a substance that resembles snow to the branches. The flocking process can be done in several ways, including spraying the tree with flocking spray or using flocking powder. The flocking spray comes in a bottle and can be applied directly to the tree. To use flocking powder, you'll need to spread the powder over the tree's branches and then gently shake the tree to allow the flocking powder to adhere to the branches. Once the flocking process is complete, the tree will have a realistic snowy look.