If he decides he'd like a Gryffindor snake pet, you can lull him into a false sense of security and wait for an opportunity to nick the pin, right?

And jokes, hmm, I think the key is to remember the punch line is less important than the setup, which should always focus on why snakes are better than other animals, Slytherins are better than other Houses, and His Pretentiousness is better than other people.