"So you say," Severus said blandly. He was well aware of the actions of his Slytherins during those classes. In spite of what some might have thought, he was never oblivious to what was going on in a room full of cauldrons. Unfortunately it had been necessary to let it happen.
He nodded and handed the vial over to Harry. He then gestured towards the door to his bedroom. "You'd best get settled in before that takes effect then."