In a large mixing bowl, combine the baking soda and citric acid. Mix well to ensure no clumps remain.

Slowly add the castile soap to the dry mixture, stirring constantly to prevent any fizzing.

Add the essential oils, mixing thoroughly to evenly distribute the scent.

Gradually add the water, a few drops at a time, mixing as you go. The mixture should resemble damp sand and hold its shape when pressed.

Press the mixture firmly into silicone molds or ice cube trays.

Let the toilet fizzies dry completely for 12–24 hours, depending on humidity.

Once fully dried, gently remove the fizzies from the molds and store them in an airtight container.

To use, drop one fizzy into the toilet bowl. Let it fizz and dissolve to release its cleaning power and scent.