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.)