In a mixing bowl, dissolve the red jello packet in 2 cups of boiling water. Stir until fully dissolved. Add 1 cup of cold water and 1 cup of chilled vodka to the mixture. Stir well.

Arrange 30 (2-ounce) shot glasses on a large, rimmed tray. Pour half of the red jello mixture into shot glasses, filling them about a third of the way. Place the shot glasses in the refrigerator and let them set for at least 1 hour.

Add the unflavored gelatin and 1 cup of boiling water to another mixing bowl. Stir until the gelatin is completely dissolved.

Add the can of sweetened condensed milk, ½ cup of cold water, and ½ cup of chilled vodka to the gelatin mixture. Stir until well combined. Let the mixture cool to room temperature.

Once the red layer is set, pour the white gelatin mixture over the set red layer in the shot glasses, filling them another third of the way. Refrigerate the shot glasses for another 1 hour or until the white layer is set.

If the remaining red jello mixture has started to set, heat it in the microwave for 10-15 seconds to melt it again. Pour the remaining red jello mixture over the set white layer in the shot glasses, filling them to the top. Place the shot glasses back in the refrigerator and let them set for another 2 hours or until fully set.

Before serving, pipe a swirl of whipped cream on top of each jello shot. Sprinkle crushed candy canes or sprinkles on top, and enjoy.