Add all dry ingredients to a large bowl and combine with a whisk or fork. Divide the mixture evenly between 3 bowls.
In 3 small cups or ramekins, add to each cup 1 tablespoon fractionated coconut oil and 2 drops of essential oil. For my Christmas bath bombs I used Eucalyptus in one, peppermint in one and a combo of peppermint/rosemary in the other.
Slowly add coconut oil and essential oil to the 1st bowl dry mixture, whisking immediately and constantly. Be sure not to add in wet ingredients all at once or it will activate the fizz prematurely.
Spray mixture with 1 spritz of water at a time in order to mix in very quickly. Continue to spray until the mixture is the consistency damp, not quite wet, sand.
Once the consistency is correct, fold in about 1 tablespoon of red or green sprinkles, or a combo of the 2. Be careful not to stir the sprinkles in, but fold them in so that they don't dissolve in the bath bomb mixture.
Separate the plastic ornaments and use the halves as scoops, overfilling each half. It's important to overfill the halves so that the bomb bomb ornament mixture gets solidly compacted and stays together. Smush the 2 sides together to form the bath bomb. Repeat (each bowl will make 2 bath bomb ornaments). Hold the ornament bath bombs from the bottom and slowly remove the top. Sit the ornament on its bottom half upright in a ramekin to allow it to dry. If you leave it to dry in the ornament the plastic may crack. Allow it to dry overnight and then put the top back on the ornament. Repeat with the other bowls.