Derek let her drag his hand back to her hip, but he continued moving, cupping her backside and kneading it lightly as his other hand brushed hair back from his face. "I enjoy having boundaries," he replied. "If I'm doing a scene, I can focus. I don't have to think about anything except how to get what I want and how to please my scene partner." It was a chance to get out of his head, not unlike when he shifted into a wolf. It was pure. Primal. Simple.