Combine the baking soda, citric acid and cornstarch in a mixing bowl. Mix well.

Add the oils and mix again.

While mixing, add the water a small amount at a time. The mixing and gradual addition helps avoid creating a reaction of the ingredients.

Now, mix in the red sugar sprinkles.

Scoop the mixture into the halves of a bath bomb mold. Press gently and overfill each side, then press the two sides together firmly. Press tightly.

Remove from the mold, and set aside to dry. Once fully dry store in a plastic bag or airtight jar.