Lynn: Tom's always running into cars in front of him at traffic lights making dents.

Max: Is he really? A wreckless type, huh? What does he do for a living?

Lynn: He is a dent-ist.

(If the student can also speak Japanese, then continue the joke.)

Max: I suppose he's had to pay a lot in damages.

Lynn: No. He usually says "sorry" and gets away with it.

Max: Don't they complain?

Lynn: It may be strange, but they don't.

Max: What are they afraid of?

Lynn: They're afraid of shikaeshi from the dentist!

(For those of you who don't speak Japanese, "shikaeshi" means revenge or getting back at someone while "shikaishi," which sounds similar, refers to a dentist.)