I’d take that gum out of the keyhole if I were you, Peeves,” he said pleasantly.
Peeves paid no attention to Professor Lupin’s words, except to blow a loud wet raspberry.
Professor Lupin gave a small sigh and took out his wand.
“This is a useful little spell,” he told the class over his shoulder. “Please watch closely.”
He raised the wand to shoulder height, said, “Waddiwasi!” and pointed it at Peeves.
With the force of a bullet, the wad of chewing gum shot out of the keyhole and straight down Peeves’s left nostril; he whirled upright and zoomed away, cursing.
“Cool, sir!” said Dean Thomas in amazement.
“Thank you, Dean,” said Professor Lupin, putting his wand away again. “Shall we proceed?

Autor: J.K. Rowling