Sirius shrugged, "there was some essay about something that McGonagall droned on about for like... ever," he finished. Surely she didn't want more detail. Sirius knew he could probably dance circles around her with what he knew on the subject. He should have said Charms. Oh! There was an idea.
"Maybe it was Charms," he shrugged again. Sirius knew he couldn't make her mad to where she left, but nothing to let her on to his motives. "It's all the same thing, right, Evans?"