An expression that means that you are a specialist in a specific domain.
Ex 1 : Thad Castle from Blue Mountain State : "Anyone who comes in my zone gets laid out, because thats what I do, I LAY PEOPLE OUT !"
Ex 2 : Thad Castle : "I beat drug test, that's what I do !"
Ex 3 : Bow Wow : Who scores de more chicks ? I mean... That's me ! That's what I Do !