He probably won't have to try especially hard. Kit's generally fairly cheerful, and is taking the whole 'kidnapped to a giant tree and given fairy wings' thing remarkably well, especially for someone her age.

"Uh-huh," Kit says, returning from the kitchen area with two bowls and two spoons. "I've been trying to figure out a name for him, but well... it's hard coming up with names for a worm that don't sound bad, you know?"