To make the white layer, sprinkle two packets of gelatin over 1/2 cup of water. Allow it to soak in a minute or two. Pour in 1 cup of boiling water and one 14-ounce can of sweetened condensed milk. Stir until everything is thoroughly mixed and gelatin is dissolved. You'll have approximately 3 cups of liquid. Allow to cool to room temperature. If, during the process, it starts to gel and thicken, pop it in the microwave for a few seconds and stir. (You will need to make a second batch of the white layer for the second half of the shots, but don't make it until closer to when you need it).