Leopold von Sacher-Masoch

She stopped. "I am beginning to enjoy it," she said, "but enough for to-day. I am beginning to feel a demonic curiosity to see how far your strength goes. I take a cruel joy in seeing you tremble and writhe beneath my whip, and in hearing your groans and wails; I want to go on whipping without pity until you beg for mercy, until you lose your senses. You have awakened dangerous elements in my being. But now get up."