Terribly Silly Incest

I woke up one morning feeling very tired. I managed to make it down to the kitchen and slumped into a chair at the table. Julie, my eighteen year old twin sister, looked very concerned about my state.

"Jason, you don't look very well this morning," she said. She bounced over to me and put the back of her hand on my forehead. "You feel pretty warm too. Are you sick?"

"I don't know," I said. "I just feel really tired."

"Well you should go back to bed then. I'll call Mom and have her call the school to tell them you won't be in."

"Okay. Thanks Julie."

I kissed my sister and she gave my cock a quick squeeze through my pants. She didn't seem very happy about going to school without me, but she was also clearly worried about me. Usually she wouldn't have left me at the house without at least giving me a blowjob beforehand.

I stripped off my clothes and collapsed back into bed. I tossed and turned for a while, but eventually fell asleep.

****

A while later I heard someone else in the house. The noises were coming from downstairs, but soon I heard footsteps on the stairs. Whoever it was seemed to be looking for me. It was probably Julie skipping out on school.

"Hello?" I called.

I didn't get an immediate answer, but a moment later I found out who it was. My big sister Angie appeared in the doorway of my room with a concerned look on her face.

"Hey, little bro," Angie said. "Julie told me you were sick and asked me to come take a look."

"Hey, Angie," I said. "Thank you for coming over. I don't get to see you very often."

"I know, I'm sorry. I get so busy with work and all."

Angie was a licensed nurse, doctor, and surgeon, as well as having experience with massage therapy and swimsuit modeling. It was hard to believe how much she'd accomplished at only twenty years old. I couldn't blame Julie for calling her over since she would almost certainly know what was wrong with me.

I couldn't help staring at my big sister's breasts as she walked closer. Her tits were bigger than Julie's, but not as big as Mom's. She had a nice pair of 35CDD boobs that bounced pleasingly with every step. I realized that since I'd been having sex with Julie regularly, I seemed far more comfortable with checking out my other sister too. I hoped I wasn't too obvious about it.

Angie put the back of her hand on my forehead just like Julie had earlier. She frowned slightly.

"So how exactly are you feeling, Jase?" she asked.

"Really tired," I said. "That's about all it is. I'm not coughing or anything."

"Okay. Let me take a quick listen of your breathing."

Angie put her ear against my chest and had me breathe normally for several seconds. I felt her breasts pressing against me, and the feeling was enough to start getting me hard. I tried to convince my cock to stay soft, but it had learned that feeling my sister's boobs was a good reason to come to life. Apparently it didn't care that Julie and Angie weren't the same person.

Soon I had a sixteen-inch tent in my sheets. I knew Angie would notice it eventually, but I had to hope she wouldn't realize that she'd caused it. If she figured out that she was turning me on, she might discover that I'd been having sex with Julie and Mom and then we'd all be in trouble. That sort of thing was incest, after all.

"How does it sound?" I asked once Angie lifted her head.

"Well... it's not bad," she said. "I think I might know what the problem is...."

She seemed hesitant to go any further. I wondered if it was because I had something bad.

"Is it serious?" I asked.

"If it's what I think it is, then I can take care of it. The thing is, it could be a little awkward. I'm going to have to ask you a question that might be kind of embarrassing for you."

"What is it?"

Angie took a deep breath. "Have you been masturbating or having sex more then usual lately?"

She blushed and I blushed too. She was right, that was kind of embarrassing. I didn't want to admit that I'd been fucking our sister and mother every chance I got.

"Yes," I said, hoping she wouldn't need details.

"Thank you for answering honestly. There's one more thing I need to test, and I need you to remember that I am acting as a medical professional right now and not as your sister."

"Okay."

"Jason, I need to taste some of your cum. And I'm going to have to jerk you off to get it."

I stared at Angie with my mouth open. She couldn't have just said what I thought she said. My cock twitched at the thought of my sexy big sis swallowing my cum.

"Well, if you need to..." I said carefully. "I don't want to stop you from figuring out what's wrong."

"I promise I'll be professional about it. I won't mention it to anyone afterward. It's a very important test to determine the cause of your fatigue. It might be awkward, but it will also feel at least a little bit good too. You can pretend I'm someone else while I extract your semen if it helps."

"No, Angie. You're being so nice to help me out that I'd feel bad pretending you were someone else. I'm glad that big sister is able to take care of me, and I know you're just doing your job. It's not like it would be incest or anything."

"Exactly, I'm glad you understand that. So many people don't get that medical procedures don't count as incest even if it's something like a sister jerking off her brother so she can taste his cum."

Angie pulled back my covers. I was already naked underneath, and my eighteen-inch cock was standing straight up. My sister's eyes opened wide as she saw how big I was.

"Is something wrong?" I asked.

"No, definitely not," Angie said. "In fact, your penis is so big that I have a hard time believing that anything could be wrong with you."

She knelt down between my legs and reached out to gently put both of her hands on my hard shaft. She seemed totally in awe of my size. My cock twitched and pulsed under her fingers as she started stroking me.

"Oh god, Angie," I said. "Even though you're my sister, the way you're jerking me feels so good."

"I'm glad you like it, little bro. Having your big sister jerk you off would be much more unpleasant for both of us if you weren't enjoying it."

"Of course I'm enjoying it. I know I shouldn't think this because you're my sister, but you're so sexy and your hands are so soft and amazing on my cock."

Angie smiled at the compliment and kept stroking me. After a few minutes she paused for a moment.

"Jason, I have another suggestion that I wouldn't bring up if you didn't seem so open minded."

"What is it?"

"I think I'd be able to make you cum faster if I were to use my mouth too. I know that seems wrong because I'm your sister, but just remember that I'm also a medical professional and I wouldn't do anything that wasn't in your best interest."

I nearly came when Angie said she would use her mouth on me. It took a lot of restraint to not show how excited I was at the idea.

"Angie, you know more about these things than I do. If you think that using your mouth would help, then you should do it. It wouldn't be incest and it wouldn't be wrong in any way because it would be for medical reasons."

"That's right. You know, you might be the easiest patient to get along with that I've ever had. Most of the time people don't listen to my advice so well."

If only she knew why I was so easy to get along with. She had no idea that I actually wanted her to jerk me off and use her mouth. Most people wouldn't be so eager to have their big sister make them cum, but I was used to having sex with family members already. The idea of engaging in incest wasn't as shocking to me as she probably thought it was.

Angie went back to jerking me off. She leaned down closer to my cock and licked the tip. I groaned and tried not to cum. I wanted to see how far she'd go, and if I came too early I wouldn't get the chance.

My big sister licked and stroked my shaft, using her tongue more and more as saw that I was okay with it. She seemed concerned that I was going to change my mind, and I knew I couldn't tell her that it was all okay because I'd done much dirtier things with Mom and Julie already.

Finally Angie opened her mouth as wide as she could and took the head of my penis inside. Her soft, full lips wrapped around my shaft, caressing it sensually. She bobbed her head up and down, taking more of my length with every movement. I soon felt my cock entering her throat, and I could see the bulge my cock made as she swallowed it. I was so impressed when she managed to take it all. Only Julie had been able to accomplish that feat so far.

"Oh, Angie," I moaned. "I can feel your throat squeezing my cock. You're my big sister and you have my entire eighteen-inch cock inside your mouth. You're going to make me cum."

Angie kept working me, bobbing her head faster and faster. Just like Julie, she didn't seem to ever need to come up for a breath. I could only hold on for about fifteen and a half minutes of being sucked off by my sexy big sister before I came.

"I'm going to cum, big sis!" I said. "Your mouth and throat are so wet and tight, and you're so sexy that I'm going to cum inside you!"

She pulled back so that the head of my cock was in her mouth instead of her throat. She needed to taste my cum, and that wouldn't work if I came directly in her tummy like I usually did with Julie.

Angie swallowed shot after shot of my cum, letting it wash over her tongue before disappearing down her throat. Seeing my big sister taking my load in such a professional way made me cum even harder. I knew that it turned her on and wasn't just business. I also knew that she couldn't admit that because it would be the same as admitting that she enjoyed incest with her little brother.

"Well, it looks like I was right," Angie said once I'd finally stopped cumming.

"What is it?" I asked.

"As I'm sure you know, every time you cum you're expelling nutrients from your body. It makes your cum very healthy to eat, especially for me or Julie because we're your sisters, but it means you need to replenish those nutrients. From the taste of your cum, I'd say you're quite low on some of them."

I remembered Julie saying something about how my cum was the healthiest thing she could eat. However, I'd never realized that cumming so much might affect my health.

"So I need to eat healthier?" I asked.

"That is one possible answer," she said. "However, if we were to go with that sort of plan it would mean a very specific, unenjoyable diet for you. We could do that if you want, but I do have a faster and easier solution."

"Really?"

"Yes. I'm afraid you might not like it though. Again, it would be purely for health reasons so it wouldn't be incest, but... we would need to do some more sexual things. You've been very cooperative so far, but I know it must be awkward for you to have your sexy big sister stroke and suck your penis."

My cock twitched at the thought of Angie doing even more things to me. I felt lucky just to have her give me a blowjob, let alone the promise of more yet to come. I wondered what she had in mind.

"Angie, you're my sister and the best doctor I know. I'm willing to follow any medical advice you give me without question. Even if you told me that you and I have to have sex every day, or that you'll have to taste my cum on a regular basis to make sure I'm healthy, I'm willing to accept that."

"I'm glad to hear you say that, Jason. The fact that you're willing to commit incest with your big sister for the sake of your health makes my job much easier."

"I'll do whatever I need to. What's your plan?"

"Well, the easiest way for me to replenish your nutrients is to feed you my breast milk. It's very similar to how it works with your cum. A woman's milk is very healthy, especially for any of her children or siblings. Because we're brother and sister, the nutrients in my breast milk should replace the ones you've lost from cumming so much."

"But... you can't produce milk, can you?" I asked. "I thought you had to have a baby for that."

"That's the tricky part," she admitted. "And it's also the part of my plan that I expect you to like the least. You'd have to get me pregnant for this to work."

My big sister wanted me to get her pregnant! I couldn't believe that I'd heard her right. That meant we'd have to have sex. Angie wanted to have incestuous sibling sex with me!

I got so turned on from the idea that I came without warning. Angie hadn't been prepared for this second explosion of semen. Most of it landed on her, soaking her clothes and hair nearly instantly. By the time I finished she was absolutely covered in her brother's cum.

"Sorry," I said.

"That's okay," Angie said. "I work in a hospital so I've dealt with much worse than this. Just between you and me, if it wasn't incest and therefore wrong, I'd be so turned on by being covered in my brother's cum."

Angie stripped out of her messy clothes and wiped off her face and head as well as she could. I almost came again at the sight of my completely naked, twenty year old big sister. Her breasts were so amazing and sexy, and her pussy was shaved perfectly smooth. I wanted to throw her down on the bed and fuck the shit out of her.

"You'd really be turned on by something like that?" I asked hopefully.

"Well, yeah. I hope that doesn't freak you out. I just think the idea of sex with my own brother is crazy hot, and now that I know how big your cock is it's even hotter."

"It doesn't freak me out at all," I said. "You are so amazing and sexy that even if you're my sister, all I want to do is slam my massive cock into your tight little pussy and fuck you until we both cum."

"Luckily we have that opportunity. Since it's for medical purposes, we can fuck each other right now and not feel guilty about it."

"You're such a good sister to me, Angie. I can't believe you're going to have sex with me, even though normally it would be incest."

"Mmm, trust me, I think we'll both enjoy it, little bro."

Angie had me lie back with my cock pointed straight up. She stood above me, straddling my waist, and positioned her pussy directly above my full two-foot erection. She was leaking pussy juices all the way down her legs onto the bed.

"I know I'm going to enjoy feeling my big sister's pussy," I said.

"And I'm definitely going to enjoy feeling my little brother's cock inside me," she said. "Now just let me take care of everything. I'm a doctor so I know what I'm doing."

Angie slowly and carefully lowered herself onto my cock, taking my entire length inside her in one hard, fast movement. She moaned so loud as she was filled up all the way by her brother's penis that a dormant volcano on the other side of the world suddenly became active. I couldn't believe that she'd taken my whole cock inside her. Only Julie had been able to do that until now.

"Holy fuck!" she screamed. "This is the best feeling I've ever had in my entire life! My little brother's cock is stretching my tight little pussy so much that I feel like I'm going to explode! Even though his cock is so big that my pussy can't physically contain it, it doesn't hurt at all and just feels amazing!"

"My big sister's pussy is so tight and wet around my cock," I said. "It's squeezing me so much and I can feel how much she cares for me by how tight it is."

"I love you so much, little bro," she said. "Now that your penis has been inside me I love you more than ever."

"I feel exactly the same way," I said. "Now that I'm inside you I know that we have a special bond that can never be broken."

Angie started bouncing wildly up and down on my cock. Nearly the entire length of my shaft appeared and disappeared inside her. She was being driven crazy by the sheer pleasure of being filled up by her brother's impossibly massive penis.

After forty minutes of intense, non-stop fucking, we came at the same instant. Angie moaned so loud as she came that the volcano she'd activated earlier went dormant again. I filled up her pussy with wave after wave of my cum.

"That's it, Jason," she yelled. "Fill your big sister's vagina with all of your cum. Make sure she gets pregnant with her little brother as the father."

"I'm cumming so hard in your pussy, Angie. You will get pregnant for sure. And it will be because of your brother when you do, because that's who you're having sex with right now."

I pumped enough sperm into Angie to repopulate most of the earth. There was no way she wouldn't get pregnant from having that much cum in her pussy.

"That was so awesome," Angie said. "Thank you for making me feel so good."

"I felt the same way," I said. "Your pussy was incredible. You took my entire two-foot cock inside it."

"Well, it makes sense that it felt so good for both of us because a sister's body is made for her brother's cock. It's been scientifically proven. That's how I was able to take you all the way into my throat and pussy. My body knows you're my brother and that it needs to stretch to let you fill me all the way up."

That explained why Julie had been able to take my cock so well too. I'd always known it wasn't because she was a slut or anything, because she'd never had sex with anyone except me. Now I knew the scientific reason for it.

"So are you pregnant now?" I asked.

"Of course I am," Angie said. She patted her tummy, drawing my attention to the soft curve that it hadn't had before. "It's only a guess, but with the amount of cum you put in me I'd say I'm probably about two months pregnant right now."

She squeezed one of her nipples experimentally, and a small jet of milk shot out. I noticed that her breasts had grown too, now that she was pregnant. They looked like they were a size 44DCDE.

"Your boobs got bigger," I said.

"Mm-hm. That can happen. I'm sure you don't mind, do you?" she said with a wink. "Anyway, since I'm producing breast milk now, we should probably proceed with the plan."

I nodded and lay down in my sister's lap. She cradled my head and guided my mouth to one of her breasts. I sucked the nipple between my lips in a completely natural reaction. It was like my body could sense what it was supposed to do. Angie wasn't my mother, but she must have been close enough to confuse my instincts.

I sucked on Angie's breast like a baby, eagerly swallowing all the milk I could get out of her. It was sweet and delicious. It probably tasted better because of how genetically similar we were.

"That's it, little bro," she cooed. "Suck on your sister's big boobies and get all the yummy milk out. Fill up your tummy with with your big sis's breast milk."

I felt so safe and loved being cared for by my sister. She held me and fed me like I was her baby, but it was kind of sexual too. My cock was fully hard, and she started stroking it in a soft, motherly way while I sucked on her tits.

Angie's breast milk had an immediate effect on me. The more I drank, the more energetic I felt. It was replenishing all the nutrients I'd been carelessly wasting lately. By the time I switched to her other breast, I felt ready to run three or four marathons.

Eventually I drained the last of my sister's milk. I was pleasantly full, and incredibly horny.

"Looks like you're feeling better," Angie said.

"Yes, I am," I said as I stood up. "I'm glad I listened to your advice because I feel so good right now. I never would have known if you hadn't been here for me."

"That's what sisters are for," she said. "That and having sex with, obviously." She looked down at my cock. "Oh wow! Jase, look at your cock! It's gotten even bigger than before!"

I looked down and saw that she was right. Not only had her milk given me more energy, but apparently it had made my cock bigger too. At an estimate, I guessed that it was precisely thirty inches long. It also appeared to have gotten thicker.