Xel has a rather existential moment as Rincewind's question hurtles him between his two species. "As far as I can make out, they're channeling agents," he's surprised to hear himself saying (it is, after all, Scraggly-san. But then, he hasn't been laiety since he was four). "They seem to act like a magnifying glass in sunlight, focusing and possibly intensifying a person's magic and directed will. But then, I don't do anything with them; you should probably ask one of the wand-bearers. They seem to think they need a lot of specific waving about and spell words. I don't know if they really do or if that's just how they concentrate their minds for a strong enough intention to focus the magic. And... that doesn't really look like one of theirs," he adds, settling more comfortably out of priest-mode and reaching over to poke the star on the end of the wand. "It might work differently."
He thinks it probably does, as he politely but firmly declines the unnatural impulse to turn into a baked potato with lots of butter, but people really have to get used to their tools themselves.