I awoke with a start, I heard the engine of a car and realised it was Drew going out to work. I looked at the clock, 4am, I wanted to go back to sleep but was wide-awake after being dragged from a deep slumber. I looked at Sam next to me; she was fast asleep, on her back with her hands above her head. I knew she would have one leg straight out and the other bent, opening access to her pussy but as she was asleep there was no chance, and anyway I needed a pee. I quietly climbed out of bed and padded up the stairs, H and Drew's door was ajar as I passed.
I took my pee and started back towards bed. As I came level with H's bedroom I thought I heard a soft moan, the door was still ajar, in fact about half open. I stopped and looked in and my curiosity was rewarded with a fine sight. H had kicked the duvet off and was flat on her back. As my eyes adjusted to the low light level I could see she had her nightdress pulled up to her midriff. The moonlight was shining in through the Velux window and I began to make out her hand, it was stuffed between her legs and she was rubbing her pussy. I couldn't believe my luck, Sam never masturbated, at least not in front of me, and so this show was a real turn on. I started to rub my cock through my shorts. H removed her hand and revealed her beautiful pussy, it was dark but I could just make out trimmed blonde curls and her pink pussy lips. H stuck 3 fingers in her mouth, sucked them slowly, and then returned to massage her clit in a slow circular motion. I couldn't believe my eyes, I listened intently, no-one else was stirring so I dropped my shorts to get better access and held my stiff rod in my hand. H was still focusing on her clit and pretty soon we were stroking in time, in my imagination it was that soft, wet pussy sliding along my cock rather than my hand. Suddenly the room lit up as headlights swept along the drive.
"Shit, Drew's forgotten something!" I grabbed my shorts and pulled them back on. I took one last look in to the room, H was rubbing her abdomen, gently circling around her navel and back down to her clit and I could have sworn she was looking directly at me. No I'm in the shadows, she can't see me. Then she rearranged her nightie and pulled the duvet across. I quickly padded back down the stairs and climbed back in to bed, lying on my back as my cock was still rigid. I needed relief but I had to be quiet so as not to wake Sam. I heard Drew clatter through the front door and clomp up the stairs.