I agree. [ A pause, and then he brightened. ] Ah! But Jon explained it to me, once. He said it's when I'm... making a joke that's only funny if you've been trying to sanitize your humor for so long that it's almost ludicrous.

[ God, that Jon Blake, eh? ] Good, clean fun? I haven't triggered it yet, but I'm sure it will come once I'm...used to this place.