SLOWLY add the wet ingredients to the dry. Drop by drop. And mix. Mixing with hands works better. Divide up and color as desired
Place a small amount of edible stars into one half of the bath bomb mold.
Fill mold. Press to pack down and fill more so it's mounding over the top. Place a small animal figurine, bead or other "patronus" onto the mound. Just make sure the patronus is big enough if won't go down the drain.
Fill the other half of the mold so it is packed and overflowing. Smoosh together and twist so that the excess presses out through the center.
If you have extra molds let it sit in the mold to dry for a few minutes or until fully dry.
If you don't have extras then carefully remove the bath bomb and repeat the steps until you use up your mixture.
I find that when I take time to color and change the designs by my very last bath bomb it's dry and has a hard time holding but the rest until then do great.