That's strange - I had thought both (or at least one: the oatmeal) were sorta anti-inflammatories. Baking Soda is used to reduce the pain and inflammation of bug bites/stings and oatmeal is notorious for its use as a skin soothing agent.
Perhaps this was a concoction created by a spankee to trick the spanker into putting something soothing on the backside!
sarah