Your child is dirty. Plain and simple.
What happens when you combine a dirty child with a bar of soap? Dirty soap and a mess where ever the soap was dropped, kicked and dragged around your house.
Simplehuman sells this hands free pump soap dispenser for a reasonable $39.99
They installed the industrial version of these things in our office recently and it did wonders. I think it’s safe to say that if you install this in your bathroom it could very well change your world