He rolls back onto his knees still staring down at me. "You did give me permission. and I am sorry for letting things get to this point, but I can't."...No."He looked away. "No," I say again with more finality. "Tell me why you can't, and save me the sob story about this being about my mortality."I remain frozen where I lay as I wait for him to answer. "It has nothing to do with your mortality, but everything to do with me," he admitted, his eyes still never leaving mine. Those gray eyes of his. St continued to tell me to cum and she wants to feel her pussy filled up. With that I unleashed a torrent of cum deep inside her. Now I love going down on her after and licking her clean (I did offer) but she refused saying she wanted to feel it inside her. She stood up put her knickers on, as she did big blob of cup dripped from her wet pussy and wet her knickers. I told her she will have to change them and st said no she got dressed and told me it was going to be a good night as she can sit. She climbed on board and ignored me as she sat with a friend.Nothing was said, neither of us made any overt gestures or advances toward the other but the foundation of our sibling relationship was subtly changing. We both felt it, we both sensed it, we both tried to ignore it; up to a point. The hormonal upheaval raging in our bodies needed an outlet and since we lived almost isolated on the farm we had a lot of time alone together so we targeted each other. Our time in school was six hours a. My cock felt as if it were deeper than ever before, her warm center bathing it with her juicy fluid and making my own orgasm arrive. Finally she came, her nails digging into my back as her pussy contracted and released over and over. Her cries filled our bedroom as she came over and over again, holding me so tightly to keep me from getting away from her. Then it was my turn, my cock shooting thick streams of my seed deep inside her. I kissed her repeatedly and softly said her name as I gave in.