Clear space in your refrigerator. Place the plastic shot cups on a rimmed tray or in a baking dish so that they will be easy to transfer to and from the fridge.
Green Layer
In a medium saucepan, bring 1 cup of water to a boil. Remove from heat and whisk in green jello mix, until dissolved. Add ½ cup cold water and ½ cup vodka; stir to combine.
Pour the green jello mixture evenly between your cups, filling them about ⅓ of the way.
Transfer the cups to the refrigerator to chill for 2 hours.
White Layer
Add 1 cup of room temperature water to a medium saucepan. Sprinkle gelatin on top of the water and set aside for 5 minutes to allow the gelatin to "bloom".
Heat over medium heat, whisking until the gelatin powder is dissolved, about 2 minutes. Do not let the water come to a boil!
Remove from heat and pour in sweetened condensed milk and ½ cup vodka, stir to combine. Allow the mixture to cool completely.
Once cooled, add to your jello shot cups, filling ⅔ of the way, leaving equal room for the last layer. You will likely have extra liquid which you can discard.
Return to the refrigerator to chill for another 2 hours.
Orange Layer
Bring 1 cup of water to a boil. Remove from heat and whisk in the orange jello until dissolved. Stir in ½ cup cold water and ½ cup vodka. Set the orange jello mixture aside to cool.
Once cooled, fill your shot cups the remainder of the way with the orange jello.
Chill for 2 more hours, or until ready to serve.
Before serving, top with whipped cream and sprinkles, if desired.
Notes
Store covered in the refrigerator for up to 3 days. Top with whipped cream and sprinkles just before serving.