Heat the beeswax and oil together in a double boiler until the wax has fully melted.
Add the clay, magnesium stearate, and chosen natural colorant. (Begin by adding in around 1/8th of a teaspoon of the colorant.)Mix everything together.
Test out the color by wiping a small amount of the mixture on your hand. Add more pigment, as needed, until you reach the desired color and consistency. If you want a more opaque color, try adding more clay or magnesium stearate.
Once you are happy with the appearance of the makeup, pour the mixture into empty chapstick or lipstick tubes for easy application.
Allow to cool and harden before using.
If you are avoiding plastic, you can pour them into small aluminum tins instead. You can then apply the makeup with your fingers or a makeup brush.
If you find that your homemade makeup stick didn't turn out quite as you would have liked, you can twist up the chapstick dispenser, and break off the makeup to melt it down and fix it.
Some pigments will naturally be more opaque than others, so it's a helpful to slightly adjust the quantity of titanium dioxide, magnesium stearate, and clay as you make each color. (I needed to increase the quantity of all 3 to get an opaque bright white stick.)