Derek rotated in circle when she moved from the bed to the door. He'd thought she was encouraging him, but then she'd moved--apparently to lock the door, which meant she didn't want to be interrupted.
His gaze shifted to the bathroom door, anticipating her next movement.
"I don't require it," he said, slowly. "Isaac tends to use 'sir'. Stiles uses the two interchangeably, along with my name." He moved closer to her, touched her face, fingers brushing her lips. "I enjoy hearing it from your lips, if you truly meant it," he added.