Melinda is a good girl- tidy, controlled, and controlling. After yet another bad breakup- Charlie said that she was too controlled in bed!- she is running off her temper when a voice begins to whisper in her ear.
There's no one there- just a voice that whispers deliciously wicked things in her ear. By the time Melinda gets home, she's hot and wet and ready for some personal time.
Then the demon materializes. With one gesture, he proceeds to show Melinda all the pleasures that she's denied herself for so long.