It was Saturday morning and as I had predicted my younger stepsister Chrissy and her friend Jenny got up with the sun.
One of them woke me up as she stomped downstairs and I rolled over and tried to get back to sleep. I must have drifted off because the next thing I heard was the front door slamming. I checked the clock on my bedside table and saw that it read 9.30am, Jenny must have left.
I heard Chrissy climb the stairs and then there was silence for 10 seconds before, to my surprise, she opened my bedroom door and came and sat cross-legged on the empty side of my queen-sized bed.
"Hey, I knew you'd be awake."
"It's difficult to sleep when there are two elephants lumbering around the house."
She stuck her tongue out at me.
"So," she said, "you'll never guess what."
"What?" I asked, rubbing sleep from my eyes.
"Jeff! You have to guess."
I sighed and studied my 18-year-old stepsister. She was small, even smaller than Jenny, about 5 feet tall with pale skin and blonde, almost silver, hair that came down to the middle of her back. Though she did not have as nice an arse as Jenny she did have some lovely tits, not that I thought about that sort of thing, she was my stepsister afterall. She was wearing a short-sleaved pink shirt and light blue jean shorts. As she waited for me to speak she ran her fingers through her hair and cocked her head to one side, whilst tapping a finger on her thigh.
"Chrissy..."
"Fine. You know Jenny came down for hot chocolate last night?"
"I remember." I said, nodding.
"Well," she said, "She'd been gone a few minutes and I was wondering where she'd got to so I came downstairs."
I swallowed. I was beginning to see where this was going.
"I got about halfway down the stairs and I saw..." she flushed, "I saw her on her knees sucking your cock."
I stared at my stepsister as she told me that she'd caught me being very intimate with one of her friends.
"So I sat there watching." she went on. "I watched her deepthroat you, I watched you come on her face, I watched you eat her out afterwards, and then I crept back upstairs so neither of you knew I'd seen you. Do you know what she said when I asked why she took so long?"
I shook my head.
"She said 'I had trouble finding everything but luckily Jeff was there to help me. He was very good.'" Chrissy smirked at me.
"I suppose you're going to tell mum and dad?" I asked.
"Why would I do that? Who you fuck is your own business. Besides," she said, stretching her arms above her head, "they might not let me have any more sleepovers if they think you're taking sexual advantage of my friends."
"I wouldn't say I took advantage of her."
"Oh really?" Chrissy raised her eyebrows at me.
"Yes. She was... curious. And willing. Very willing."
"Anyway... I'm not going to tell on you-"
"Why not?" I broke in.
"I'm not going to tell on you," Chrissy repeated "If... If..."
"If what?" I asked suspiciously.
"Oh come on! Isn't it obvious? I had to sit there while you ate out my friend."
"You didn't have to watch. But I still don't understand what you want."
"I was turned on!" Chrissy exclaimed. "I was horny, and then I had to go back upstairs and pretend that I was oblivious. I tried masturbating in the few minutes before Jenny woke up but that didn't do it for me."
I stared at her, not saying a word, and Chrissy let out a dramatic sigh.
"Are you going to make me say it? I need you to make me cum!"
"What?? Chrissy you're my sister!"
"Stepsister. We're not biologically related."
"That's a big word, I'm surprised you can pronounce it." She stuck her tongue out at me again and then looked down and stared at where my cock was beneath the duvet.
"Of course," she said, "I'd make it worth your while." And she moved her hand so it sat on top of my duvet-covered penis.