Add the melted shea butter, jojoba oil, and glycerin to a medium-size bowl. Sprinkle the xanthan gum over the top. Allow the gum to rest for 1 minute. During this time the powder should sink into the liquid. After 1 minute, use the immersion blender to dissolve the gum into the oil mixture--pulse the immersion blender for 1 minute. Add the castile soap and warm water to the bowl. Place the immersion blender at the bottom of the bowl. Blend the mixture with the immersion blender for 1-2 more minutes, pulsing up and down. The mixture should turn into a creamy lotion-like consistency during this time.Pour the shower gel into a soap dispenser. I found my container (pictured) at Target.While the mixture won't separate, I recommend giving the container a gentle shake before each use. When you introduce water into a product without a preservative you always run the risk of introducing bacteria, so use water-based products quickly.