"I'm not teasing. I'm pointing out how short sighted you are being, which really is not a Slytherin characteristic." Yes, he was going to milk this for all his worth, because Cass really should have been sorted in a different house, any of them, in fact.
"I can follow orders when there is a reason. It's how I got in charge," he said, grinning. "However, following your orders is rarely a good thing." He kissed Cass again. "I'm glad you feel better, though."