Turn Rachel into my sex and fuck her

Rachel stands up and turns around to face me while she continues to lustfully stare at my big, hard cock. "I'm sorry. What did you say, Rachel? I didn't hear what you said." Mom says, slightly upset that Rachel isn't shaking and showing her ass anymore. "What? Oh! Why did you call John Master, Mom?"

"Because John is my Master. I am your brother's sex ****. And soon, you'll become your brother's sex **** as well." I can tell that Rachel is shocked by what mom said. But she still hasn't looked away from my cock yet. "What?! Sex ****? I don't understand."

"It's okay, Rachel. I too completely forgot about the tradition we had to follow when Master turned 18. Don't worry. Master will remind you all about the tradition. Go ahead, Master. Remind your sister about the tradition." Mom is definitely proving herself to be a good sex ****. I'm going to have to come up with a way to reward her. Maybe just fucking mom again is a big enough reward. "There is a very important tradition that a family must follow when a son turns 18. On a teenage boy's 18th birthday, his mother will become his sex **** and serve him for the rest of her life. The same rule applies if the son has a sister who is 18 or older. Since you're my sister and you're 20, the tradition says that you have to become my sex ****. You want to become my sex ****, Rachel. You want to serve me and my big, hard cock for the rest of your life. Mom has already become my sex **** and is very happy being my sex ****. Isn't that right, Mom?"

"Yes, Master. I enjoy being your sex ****. Come on, Rachel. It's not too late to follow the tradition. Become your brother's sex **** so we can serve him and his big, hard cock together. Trust me when I say you're going to love serving your brother as his sex ****. His cock is amazing."

"W-Wait? So, are you saying that you and John had sex?" From the tone of Rachel's voice, it sounds like she's more turned on than disgusted by the idea that mom and I had sex. Mom starts to talk before I can. "Yes. You should have seen me when Master was fucking me. He even came inside my tight, slutty pussy. Master released so much cum inside me, there's a good chance that I'm pregnant with his child." The app already told me that I successfully impregnated mom. But I'm not going to tell mom. I think I'm going to let her find out about it on her own. "The thought of mom and me having sex is turning you on, Rachel. And the idea that mom might be pregnant with my child is turning you on even more." Rachel starts to play with herself again. "W-What do I have to do to become your sex ****, John? I want to fix my mistake of not following the tradition we have to follow. I'm so sorry I didn't become your sex **** on your 18th birthday, John. Just tell me what I have to do to fix it."

"You're going to have to let me fuck and cum inside your pussy, Rachel. But you also have to agree that you will call me Master from now on and that you'll always obey me. You must promise me that you will serve me and my big, hard cock for the rest of your life. Your body, mind, and soul belong completely to me now, Rachel. Do you understand?"

"Yes, Master. I understand. I promise I'll serve you and your big, hard cock for the rest of my life. I promise I'll always obey you and do whatever you want me to. Just one thing I want to say real quick before you fuck me, Master. I'm a virgin. So, can you please fuck me slowly?" I grab my phone and type, Rachel will not feel any pain when having sex. Rachel will always feel massive amounts of pleasure when having sex. Rachel is able to live forever and will always stay healthy. After I tap enter, I say, "Don't worry, Rachel. I'm sure you're not going to feel any pain while I'm fucking that tight, slutty pussy of yours. Also, you don't get to decide how I fuck you. You are my sex ****. I am your Master. I make all the decisions. Do you understand, slut?"

"Yes, Master. I'm so sorry, Master. Please forgive me." I put my phone down on the table that's in the living room. "It's okay, Rachel. I forgive you. Mom and I will teach you everything you need to know about being a good sex ****. But right now, we have a tradition we need to complete. Turn around and bend over for me, slut." Rachel does what I tell her to do, and I'm now looking at her big, round ass again. I position myself right behind my sister and line my cock up with her pussy. "Are you going to fuck me and take my virginity right in front of mom, Master?"

"Yes, Rachel. I am. You don't have any problem with me fucking you while mom watches. You love it when I fuck you in front of mom, Rachel. And mom. You love watching me fuck Rachel." Not wanting to wait any longer, I start to slide my cock inside Rachel's pussy. I have a bit of a harder time pushing my entire cock inside her pussy than I did with mom's pussy. As soon as I slide my cock fully inside my sister's pussy, I start thrusting. I can't see Rachel's face. But I can already tell she's enjoying me fucking her due to her loud moans filled with pleasure. I look down at Rachel's ass and watch it bounce with every thrust I make. I spank Rachel's big, round ass hard as I remember what the app said about Rachel.

Rachel's pussy squeezes tighter around my cock after I spanked her ass. She only continues to moan and doesn't say anything about me spanking her ass. I spank Rachel's ass again, then a third time. I continually spank Rachel's ass for the next, I'd say, maybe 5 minutes until I finally stop. About a minute later, after I've stopped spanking my sister, Rachel speaks for the first time since I've started fucking her. "W-Why did you stop spanking me, Master?! Can you please go back to spanking my ass again, Master?! Please?! It felt so fucking good when you were spanking my ass!" I smile as I go back to spanking my sister's ass. "Tell me how it feels to lose your virginity to your own brother, Rachel. Does my big, hard cock feel good inside your tight, slutty pussy?"

"Y-Yes! Your big, hard cock feels so good inside my tight, slutty pussy, Master! I had no idea your cock was so big! Thank you so much for taking my virginity, Master!" Rachel turns her head toward mom. Mom is sitting on the couch while vigorously rubbing her pussy and squeezing her big titties with her other hand. "I'm so glad you saw Master take my virginity, Mom! You watching Master fuck me is turning me on so fucking much! How long has Master been fucking me, Mom?!" Mom looks at the clock that is underneath the TV. "Master has been fucking you for a little more than an hour now."

Wait? Have I really been fucking Rachel for over an hour? I feel like I've only been fucking Rachel for maybe 15 or 20 minutes. I guess I was so caught up in enjoying the pleasure of my sister's tight, slutty pussy that I didn't realize how much time had passed. I even lost count of how many times I've made Rachel cum. "Oh my god! Really?! I can't believe you've been fucking me for an hour and haven't cummed once yet, Master! You have to be getting close to cumming now! The tradition says you have to cum inside my pussy, right, Master?!"

"Yes. That's right, Rachel. Why do you ask?" I spank Rachel's ass again after I say this. "Does the tradition say that you have to impregnate me as well, Master?!"

"Uhh... No. I don't have to impregnate you in order to complete the tradition. But there's a good chance that I might impregnate you with my child after I do cum inside you. How would you feel if I did impregnate you with my child, Rachel?" Rachel doesn't answer me right away as she thinks for a moment. "W-Well, I'm not really sure how I feel about you impregnating me, Master! I know you told me that you came inside mom and that she might be pregnant with your child! How are you with the idea that you might be pregnant with Master's child, Mom?!"

"Oh! You have no idea how badly I'm hoping that I'm pregnant with Master's child. Before Master came inside me, I begged him to impregnate me. I want Master to impregnate me with many children. You should say yes to wanting to be impregnated, Rachel. Master is going to cum inside that tight, slutty pussy of yours anyway."

"I-I'm happy with you impregnating me with your child, Master, as long as you're happy with it! Are you hoping that you do impregnate me after you cum inside me, Master?" I've already successfully impregnated my mom with my child. But do I also want to impregnate my sister as well? If I do, then they'll give birth around the same time. I don't know anything about raising a kid. And I don't think I can just magically make my daughters turn 18 immediately after they are born.