D.P.
You've gotten some great responses from moms -- here is a response from a former tantrum thrower. When I was young whenever I started to work myself up into a tantrum my mother made me drink -- water, milk, juice, whatever was on hand. The rule was I had to finish the bottle or cup before I could continue crying and I had to drink normally -- no gulping. Her theory, as she told me later, was that you can't throw a tantrum and drink at the same time. It's physically impossible. And usually by the time I finished the drink I had calmed down enough that there was no tantrum or it was greatly reduced.
I don't know if I appreciated all the beverages at the time, but as an adult I have to give my mom props -- this was a pretty clever trick!