Mix the baking soda, citric acid and coco powder together. A blender or food processor is helpful to ensure their are no clumps.

Mix in the vanilla oil and water. Make sure to be stirring while water is added, to minimize the reaction.

Scoop mixture into 5 of the mold cavities pressing down to compact as you add. The recipe should make exactly 5. if you have any left compact more.

Set the mold with bath bombs aside to dry.  I suggest waiting until they are fully dry before unmolding (at least a few hours). The top of the swirl may be prone to breakage otherwise.

Once dry, pop the poops out of the mold. Cut a few smile stencils out of paper towel. Put on a glove** and hold the towel stencil onto the bath bomb.

Mix a few drops of water into confectioners sugar to create a thick icing. Dip the back of each eye candy into the icing and stick it in position on the poop bath bomb. Turn the little characters on their side, with help of towel, mold, etc. This ensures the eyes stay in place while drying.