Harry wanted to wisely retort that he did, in fact, prefer to be caught at it by portraits or Narcissa Malfoy than to be here in his room, but wisely chose to keep his mouth shut - though he did roll his eyes.
He gave a non-committal sort of grunt of both acquiescence and agreement. He'd prefer not to have to splinter his mind either, but here he was. "Snape started teaching me, and it was rather... rough. And instructionless. And he stopped halfway and never gave me another class, because I accidentally saw something of his, and I apologise in advance if that happens again." Harry relaxed into the chair, leaning back more or less comfortably. It was then that he spotted Draco's wand, out and at the ready. It occurred to him that Draco was possibly planning on surprising him with it rather than warning, as at least Snape had had the decency to do thirty percent of the time. But then something else occurred.
"You can't use your wand for this, Draco. They check it."