It started out simple enough, the aftermath of a drunken night schmoozing with big wigs, at a gala held in the castle. He helped me back to my room...and before I knew it...I was fucking my brother Elias. I was inclined to never do it again, but when we talked about it, that only lead to more sex. From then on, the two of us were hooked. We fucked whenever we thought we could get away with it, day or night. Now of course, him being my brother, I was extra careful about birth prevention measures. He always wore a condom, that we would inspect at least twice, and we never did it on one of my unsafe days. Just when I thought we had this nailed down to a science, it happened, but "it" may not be what you're thinking. One morning, I had passed by my father, sitting out on the veranda, having a cup of coffee while reading the paper. "Good morning my dear." He said cheerfully to me. "Morning daddy."  I had already started to pass when he spoke up again. "Might I ask when we should be expecting an heir?" I froze in my tracks, stunned my father would ask such a question. "Father, not that it's any of your business, but Sonic and I have broken up!" Without looking up from the paper, he continued "Not with that ruffian. I meant with Elias." My eyes went wide, I turned and ran into the castle. I'm not sure how or when my father found out what my brother and I were doing, but I wasn't sure if I should be more surprised that he knew or by what asked. Did he really want me to have a child with my own brother? 


   A few days later, my mother had stopped me and asked if I would have some tea with her. We sat at the kitchen table and she brought the cups over, I spoke up. "What did you want to talk about mother?" She took a long sip and slowly brought the cup down with both hands. "My daughter, it has come to my attention that you avoided a very serious question that your father asked you the other day." My heart was in my throat. "...Mom, what are you saying?" She sighed and looked out the window "I had thought that when you had started having relations with Elias that you were finally going to start taking your role as princess seriously. You had ever cut ties with that blue buffoon. Your father and I had hoped that this meant you were at last going to produce an heir that was suitable to our needs, but I can see now that is not the case." I stood up abruptly from my chair and slammed my hands on the table. "Of course it's not! What you're talking about is my brother getting me pregnant! Why are you even okay with us having sex?! That's not normal!" My mother seemed unphased by the outburst. She responded calmly "Because, at all costs, the Acorn bloodline must remain pure. I didn't want for it to end this way, but you should probably take a seat or you may fall over." I was very confused "What are talkin-" just then, I started to feel woozy and began to stumble. I looked to the cup of tea and then to my mother, before passing out. 


   I awoke in a daze in an unfamiliar surrounding. I looked around to see both of my parents standing in a doorway, at the end of a long staircase. All the while, I had felt a strange feeling in my pussy. I looked down to find my brother eating me out. I had realized too late, what was going on. "No, wait please!" "They had already closed the door. A sliding hatch allowed my father to speak. "You may come out when you have fulfilled your duty and not a moment sooner." The hatch closed and I was all alone with my brother, laying on a king sized bed in some kind of dungeon below the castle. I pulled his head away from my crotch. "Elias stop, what the hell do you think you're doing?!" He stood up on his knees and wiped his mouth of my juices. "What we should have been doing all along. Furthering the Acorn lineage." I could see he had a massive hard on. "Elias, this is insane, I'm your sister, you can't get me pregnant!" He had a look of determination in his eye. "It'd be quite simple actually." Before I knew it, he was on top of me. He pressed his lips against mine and forced his tongue inside my mouth. Meanwhile, he was grinding his dick against my clit. I tried to fight him, but it all just felt too good. He penetrated me. "Oh God sis! Your pussy feels so good raw!" "Please Elias, don't do this." "There's no stopping now sister, I will impregnate you. Please don't be sad, this is a joyous occasion, you should be enjoying this as much as I am." I couldn't find the words to respond as I lay there getting pounded by my bother, looking to knock me up. "Soon, my seed will flow forth, penetrating your inner walls and finding their home in your fertile egg." How did they even know this wasn't one of my safe days. Just how closely have they been watching me? 


   "Feel my dick pumping in and out of you sister, for it will be the tool which will plant new life within you. I know you're secretly enjoying this Sally. You've always been such a slutty sister, haven't you?" As much as I didn't want his words to be true, I couldn't resist the feelings he was stirring inside me. "Now sister, I want you to beg for it. I want you to beg me for my cum!" A voice I wasn't even sure was mine burst forth, without my consent. "Yes, please! Fill me with your cum! I need to feel it deep inside! I need you to get me pregnant!" Elias obliged and soon I was filled to the brim with his seed. He pulled out, and a floodgate was released, he had cum so much. Shortly thereafter, our mother opened the door. She came over to me and spread my legs, staring intently at my pussy. She stuck a finger inside me as deep as she could, making sure Elias had done his job. She pulled it out and put it in her mouth, licking it clean. "Excellent work, but we must be sure, so I will leave you down here a bit longer." She walked back up the stairs, leaving my brother and I to procreate. We fucked for hours, and every time he'd cum, he made sure to pour every drop inside of me. I hadn't known I wanted this, but now I realize it's what I was made for. Six months later and I gave birth to twins, one boy and one girl. Elias and I couldn't be happier.