Heine makes a noncommittal sound in reply—he doesn't know why either. His guess amounts to the idea that wandless magic means letting go of an aid that's been with Jade for most of his exposure to magic.

"Maybe because they were hitting you." For a kid, Jade's surprisingly collected nearly all the time. There had been something, though, when he'd gotten clearly angry and managed a proper Shielding Charm.

It's idle conjecture on Heine's part, anyway; he starts up the charmed slingshot again and hops to sit on a desk to watch.