There are a few different ways that you can make cold foam, but the best way is to use an immersion blender. First, you will need to add some cold water to a cup or bowl. Then, you will need to put your immersion blender into the cold water and turn it on. Blend the water for about 30 seconds, or until it is foamy. Next, you will need to add your desired ingredients to the foam and blend again for another 30 seconds. You can then pour the foam into a glass and enjoy!