She knew! I braced myself-it would be the end of my private little world-and took her silence to mean anger. I finally found the courage to look Laura in the eye.

"Oh, Kim," she said. "I've known about it for days. I saw a really sexy film the other night and went to play with myself before I went to bed. And I saw someone had replaced the batteries. I knew it could only have been you."

"You're going to ask me to leave, aren't you?" I said, wondering how I could have been so stupid. I turned my back on her, too ashamed to meet her gaze.

Laura didn't say anything. She's really angry, I thought. She's really dragging this out. The silence was excruciating. Then I heard the flick of a switch and a familiar buzzing sound.

"On the contrary," she said. "I now have an even bigger incentive to make you stay."

I could feel the warmth of her behind me, and when she ran the vibrator down the length of my spine I let out an involuntary moan of pleasure. I sat perfectly still, although inside I was on fire. Laura trailed the sex toy over the small of my back, then rolled it between my shoulder blades before using it to press gently on the skin behind my ears. I'd once told Laura that this inch of skin was the most sensitive erogenous zone on my body and that any man who knew to kiss me there was virtually guaranteed to get me off. She exploited her secret knowledge, pressing the toy against my neck, turning it down to its lowest setting, where it tickled me like a feather, creating a current of arousal that flowed directly to my pussy.

Close behind me now, Laura reached her free hand around and parted my bush.

"God, you're soaking," she said, sliding a finger into my pussy and then putting it to her lips. I felt embarrassed until she turned me around. Her own legs were parted and her thighs just as damp as mine.