A slow grin spread across Sirius' face; he'd managed to surprise her with his question. Well, good. He'd managed to surprise himself with it, too — he hadn't planned to ask her to dance, and hadn't really thought it through. He supposed that he was glad that he had.

He offered him her hand after she shrugged at him. "Come on," he said, "It's a waltz, just like etiquette class."

(Was she any good in etiquette class? He had to hope that she was, as otherwise she was going to step all over his toes.)