Nick: [repeatedly poking his mother in the ribs] Watcha doin? Watcha doin? Watcha doin? Watcha doin?
Mom: [lets loose a punch] STOP IT! I HATE THAT!
Nick: [laughing] Is that all the harder you can hit?!
Mom: [standing] No. Of course not.
Nick: [taking boxer stance] You've seen Fight Club, right? I want you to hit me as hard as you can.
Mom: Really? Are you going to hit me back?
Nick: No. I can take a punch.
Mom: OK. [draws her fist back and lets it fly]
Nick: That's pretty good. Was that your hardest?
Mom: No. I can hit harder.
Nick: [Takes stance and pats bicep target]
Mom: [Let's it fly]
Nick: That's Ok. [begins demonstrating] But, you should do this with your fist and step like that and so forth.
Mom: Oh. Ok.
Nick: Try again.
Mom: [Lets it fly. A loud "POP" is heard]
Nick: [Takes a rub at his arm] Didja hear that? Much better.
Mom: I think I got it now. Can I try again?
Nick: Nope. I'm done. [Returns to sofa]
Check out Wikipedia for a more academic overview.
WARNING: Rough language ahead