Found this recipe for homemade finger paint on Pinterest:
The creator of the recipe did mention that the texture might be lumpy if you add too much cornstarch and advised to thin with water.
My paint did come out lumpy:
So I thinned with water, but still not satisfied, I ran my immersion blender through it.
Sooo much better:
We had fun doing some plain old finger painting:
Some arm painting:
I then put out a piece of aluminum foil and bubble wrap to contrast painting on smooth vs bumpy surfaces.