All participants are over 18.
Laura and I had made love twice more in the night before falling into an exhausted sleep. I woke up in the morning to find her spooned up against me and my raging hard on. Propping myself up on an elbow, I allowed my gaze to move over her body, stopping to admire all of her strong points. Her ass was great. Large and unblemished, smooth and taut. Her boobs were tremendous. I had previously guessed C cups but now I was leaning towards D's. Even lying on her side, there was little sag to them, they stood out proudly from her chest. Looking everywhere, my eyes went to her face and I could see the strong family resemblance. Even though we had been raised by separate parents in different provinces, there is no doubt that anyone that met the two of us would guess us to be brother and sister. And, my sister really was a fox. Nothing small about her but nothing grossly large either. She was just a big boned girl with a body that didn't quit.
My cock was only semi-hard at the moment, mostly my early morning wood, and it was laying between the cheeks of my sister's ass. As I thought about where it was, it began to grow. Not morning wood now, a full blown erection was growing. I could feel its length growing and sliding further between her thighs, slipping past her asshole, and into her pubic hair. Still not moving, I gloried in the feeling of being this close to my sister and her pussy. I was still in a mood of some disbelief that I had fucked Laura the night before. Not once but twice had my cock slid into my sister's pussy. That was still so unbelievable. I could see in my mind's eye her and my cum mixed together and splashed all across her thighs. Yup, no doubt now, my cock was at its full six and a half, almost seven, inches and straining to return to the home it had found the previous night.
My hand had been resting gently on her breast. Without much thought, I started to flex my fingers, squeezing Laura's breast, feeling her nipple starting to grow under my palm. Still gently, I began to use the muscles in my groin to flex my cock between her thighs. I could feel her pubic hair rubbing against it. In moments, Laura's hand was resting on mine, and forcing it to grope her tit even harder. My sister started to rock slowly back and forth causing my cock to slide even further against her pussy.
Enjoying the feeling, I was surprised when she lifted her leg and then reached between our bodies to line my cock up with the entrance to her pussy. As I started to lunge forward, my sister pushed backwards and soon enough I was balls deep in her pussy. Her pussy was so tight. Laura's pussy was much tighter than my wife's. Tighter than most of the women I had been with before. The tightness was causing me to want to shoot my load almost right away. I forced myself to lie quietly, not moving, while I got my balls back under control.
"Oh, Laura," I muttered quietly, "you are killing me..."
There was no response from my sister except that I could feel her muscles tightening her pussy around my dick. I was still trying to lay unmoving so as to prolong the experience. It became even more difficult as my sister once again began to push herself back and forth while clenching and releasing her cunt muscles. It was no use, I couldn't hold back. I reached around her to find her clit with my exploring hand. Seizing it gently between my fingers, I began to slowly roll it back and forth between my fingers, sometimes stopping to flick it lightly.
I could feel the semen growing in my cock, coming ever closer to shooting off. But, I could also feel my sister's body tensing as orgasm approached within her as well. It was becoming a race to see which one of us would let go first. I didn't want to leave her hanging with me having to run off to work soon so I concentrated on calming myself and retaining control. Still my cock slid in and out of Laura's pussy with her controlling the speed.