When he emerged, he was wearing a towel wrapped around his waist. As he sat on the bed, it swung open, and I couldn't take my gaze away from him. He was scorching.

"Limits," he said as he leaned against the headboard. "But first, let's make sure we're all on the same page with what we're doing."

"OK," I grumbled. I was humiliated; I'd never done anything like this before, never entered a sexual relationship so coldly with a particular purpose in mind. But how else was I supposed to discover this strange new world?

"I'll be here from Friday afternoon through Saturday night for the next eight weeks," he...