His hand soap recipe from One Green Planet I find amazing for the kids in the bath/shower. It's foaming so it's great for them to only use a small amount.
DIY Foaming Pump Soap
2 Tablespoons castille soap
15 drops Essential Oil of choice
Mix castille soap and essential oils together.
Pour into your pump container and fill water slowly to the top (you may need to let the bubbles settle occasionally)
Screw on lid. Shake around.