To tap the genitals of another with your hand or an object. Doodlebops are not meant to be violent or painful. They are a sign of affection and onesupsmanship. Can be used as a noun, verb, or exclamation.
Noun: "While we waited in line, Fred gave me a good doodlebop."
A doodlebop is a thing. It's any object - any thing that's a thing. You know when you're snapping your fingers and you can't come up with the right word for something? It becomes a doodlebop.