"I believe so." To be honest, he wasn't quite sure if the sound came from the flashing lights or the waving stick, because he'd heard it in association with both on the telly, but. But he couldn't exactly summon William a muggle police car, and it's not like anyone else here was an expert on muggles.
Other than the muggleborns, that is.
"Regardless," he said confidently, twisting to retrieve his drink again. "It's not as though I'm filling out these coconuts precisely as muggles intended, so really, isn't it the effect that counts? Give it a little swing."