I poured out another full load, and what felt like many times more, into her cramped, thirsty, passage. I drenched her cervix in hot seed, not caring to ask if she took precautions, knowing, even as I filled her up, that my sperm could right now be swimming into my sister’s womb and seeking an egg to impregnate.

In that moment I could not have cared less.

As the last sputtering spurts were pumped into her from my depleted balls I sucked in ragged breaths, dr****g my naked body heavily across hers. When I finally released her mouth she too was panting and barely able to stay up. At the same time she seemed to buzz with a satisfied energy that, if she were a cat, I could have sworn would have manifested as a purr.

She buckled and I went with her, down onto the sofa. When I rolled off her, resisted by the sticky, clinging sweat and body fluids between us, my drained cock slipped out of her snug channel. A thick mess of white come was squeezed out of her contracting vagina. It narrowly missed the sofa cushions and, rather fortuitously, began to form a decent sized puddle on the floorboards between our feet.

I only realized this later because, even before her head hit the sofa cushion, my mouth was on hers and we met in a far more gentle, passionate kiss than the one before. I knelt beside her as she turned her face to meet mine. We could hear each other breathing hard through our noses as our tongues slid over each other.

I might have carried on like that until I grew hard again which, given my sister’s effect on me, would not have been very long. But, Casey broke the kiss and pushed me back. It had none of the force and aggression she had shown me earlier, but the wide-eyed expression she gave me made me pause.

“Mom!” She hissed.

“Shit!” I had completely forgotten in my overwhelming lust.

“Uh” I stammered as I vacillated over what to do.

“Pick up the phone,” Casey whispered insistently. “Go!”

I stood up on shaky legs. Casey came up with me. More of my seed slopped out of her as she moved, adding to the already impressive creamy puddle on the floor. I hesitated over it, knowing it would have to be cleaned up but Casey shoved me. “Leave it and go and talk to mom!”

She was right. Already too much time had passed. I gave her one last look and then made a dash for the phone. Casey moved fast in the other direction, back towards her bedroom, her hand cupping her sex in an attempt to catch my come, which was still dripping out of her and running down her thighs. She gave me one last enigmatic look over her shoulder, before she moved out of sight.

I knocked the cushion off the phone and picked it up. I had the presence of mind to turn the phone away from me so that my mom was not presented with a close up of my junk, still semi-erect and dripping with my sister’s juices.