Impregnating my Unsuspecting Sister

So let me start with me. My name is Scott. I’m 25 years old, average build, blonde hair and work too much. I had recently moved back in with my parents as I had broken up with my girlfriend. So I was now living with mum, dad and my much younger 13 year old sister.
My sister’s names is Lauren, she is very tiny for her age, at only 4”6’ tall she looked more about 11 or 12 maybe. She has long blonde hair, blue eyes, tiny a cup’s, but let’s be fair since she is only 13 and just really hitting puberty. She is however very slim and athletic, tight and flat tummy, nicely forming hips and a heavenly little bubble butt. She is a gymnast and trains really hard and as a result she is very fit and also very flexible.
Now to begin with I just went about by business and she went about hers. After a few weeks had past my mother asked me to take Lauren to her gym class one Friday morning. While not happy I agreed and got ready. I drove Lauren into town and we headed into the gym centre. I went and sat on the side with the other parents to wait. When Lauren was stripping off her track pants and jacket I saw her for the first time in her very tight leotard. The sleeves run from her wrists in pale baby pink up her slender arms and over her shoulders. The tight fit over her newly budding breasts, holding them firm and round, the leotard also had little shiny sequins scattered over her breasts. The pink leotard flowed down from her breasts and firmly over her beautiful flat tummy and continuing down to a tight little V shape covering her pussy and nicely flowing between her legs and disappearing. Lauren then turned around and lent forward to place her clothes into her bag. The site was just amazing to see. The baby pink leotard came off her shoulders and ran down her back, showing off her forming hips on the way. Then tightly flowed over her wonderful little bubble butt. The sides of her leotard gripped firmly to the sides of her butt cheeks, keeping then covered and hidden from view, and all this leading down to another lovely V disappearing between her legs.
I hadn’t had a fuck in 3 months, given my bad relationship and then breaking up and moving back home. I couldn’t help but feel my cock getting firm. I was so surprised by the sight in front of me, my sister, barely even a teen, turning me on in a way I hadn’t ever felt before. Even with all the other girls their and many of them older and more developed, I couldn’t stop staring a Lauren her entire session.
When we were finished we headed home. My intention was to get home and head to my room and jack off a load. When we got inside I saw Lauren head into the kitchen and get out some tablets and take them. I had to ask her, “What are those you took?”.
“Pain tablets, I get really sore after sessions, so I take them during the day when I need to and I take sleeping pills after I get home for night sessions if needed”.
Instantly I got thinking about it, what it meant and what it meant for me. I decided not to stroke out a load this morning, but I did advise mum that I would take her to training this afternoon after school. This also allowed me convince my mother and father to head out for the night, have a nice dinner and movie and even a few drinks. I knew this meant they would not be home till really late.
Lauren arrived home from school, and I advised her that I was taking her again. She went and changed, returning in the tracksuit again. We hope in the card and headed back into town. Just like the morning we arrived and I headed over to the parents waiting area. And again just like the morning Lauren took off her track pants and jacket, revealing her super fine, tight and very young body to me to look at for the next hour or so. However this time she was wearing a shiny, metallic white leotard. It shined all over and again had sequins glittering off her chest. The leotard looked maybe even a bit tighter than the pink one from the morning. It flowed very firmly over her tiny pussy, tight enough to really show off her mound underneath. I was ready to burst in my pants right then, but knew I had to hold it. Again, just like the morning I only stared at Lauren the whole session.
We arrived home and both headed to the kitchen. I made some light pasta for dinner and we ate quietly at the table. When I was done, I offered to get Lauren her tablets and a drink. She accepted and I headed to off to the bench. I got out her tablets, and unpacked 6 of them. I knew she only needed 2 at a time, but I wanted to make sure my plan would work. I dropped 4 into the glass of orange juice and stirred it around for a few seconds. Heading back to the table I said “Here you go little sis, drink and tablets.”
“Thanks for being so nice Scott. And thanks for taking me to gym.”
About 15 minutes pasted and I hadn’t seen Lauren, so I decided to go see where she was. I heard a soft noise coming from her room, so I went over to her door and listened. I could hear soft moaning coming from inside. I knew full well what she was doing. My cock instantly got super hard. I had to see this, so I very gently took hold of her door handle and turned. It opened easily and quietly, so I slowly opened the door about an inch. Looking through the gap I could she her lying on her bed with her white leotard pulled to the side and her pushing about 6 inches of a dildo into her tiny young pussy.
I couldn’t have asked for a better view and situation. I was mesmerised by the site of her tiny, tiny little vagina. I was even more excited as I knew this also meant that her young hymen was certainly broken. I watch her as she drove herself into an orgasm over the next 10 minutes. I could feel my pre cum leaking into my underwear, dampening the front of my pants. Lauren finally peaked, whimpering, while biting her lower lips to stay quiet. She shook all over, raising her hips up and down till she blew. She pulled out the dildo and I could see her fluids start to flow out of her slit, but then she took her leotard and pulled the crotch back over herself, covering any further view. I left the door and headed to the kitchen to get a drink as well.
15 minutes later I returned to her room. Peeking through the door I could see Lauren hadn’t moved from her bed. I softly called her name.
“Lauren, you wake. Lauren.” I got no response so I opened the door and headed in. Lauren was lying on her back on the bed. Her head on her pillow and her body out flat and her legs were now stretched out straight. I just stood there looking her over for a couple of minutes, admiring how her tiny, short little body looked so hot in the leotards. I carefully got down beside her bed and put my hands on her shoulders and gave her a firm shake. I got no response from her tiny body.
At the stage I noticed under the edge of her pillow her diary poking out. I figured it couldn’t hurt to have a look. I now sat down beside her on the bed and picked up the small book. I opened it and found the last page written on. I then went back a dozen pages and started reading. My jaw hit the floor right away.
“So today I’m not feeling well, I’m having only my 3rd period ever. They started 2 months ago. I don’t like them as I feel sick and my tummy hurts. I asked mummy about it and she said it all normal and that if I don’t get used to it by my 14th birthday she will put me on the pill, which apparently stops the pain. I don’t know if I want to wait 8 more months. I asked mummy about what it all means and she said we can talk about it later as well. I don’t know why I have periods, but one of the girls at school told me that it means I can have babies. I don’t even know what men do to us during sex to make a baby. I know they put their thing inside us and then we get pregnant. I want mummy to tell me more.”
Moving on a few days, till about a week ago I start reading again. “Mummy has told me about boys making love and babies inside girls. She told me about how they put their boy’s thing into our girly part and then they fertilise our baby seed, making it turn into a baby and making us pregnant. She still didn’t really explain what they do to make this all happen. I will ask her again soon. Also, I have found one of mum’s sex toys, a dildo I think. I want to try playing with it. The girls at school said you put it into your privates and then move it up and down. I will try soon.”
I couldn’t believe what I was reading, Lauren was a tiny young girl and has only just started to explore her body, with puberty kicking in and her need for answer she was taking things into her own hands. All the while all I could think about is that I knew if I did anything she wouldn’t know or understand what it all meant anyway. I could get away with it completely. I turned to the most recent page. It was dated for yesterday.
“I am feeling like I want to try mum’s toy. I have been scared till now, but I feel like I have too or I’m going to explode. The girls at school said it’s called being horny. I don’t really know, but I want to find out. I am going to try it tomorrow night after gymnastics. I will be quiet in my room and see. I will let you know how I go.”
So tonight was Lauren’s first orgasm and the first time she has tried playing with the dildo. I was on the verge of blowing my load into my pants. I had to get underway now or I wouldn’t make it. I slowly turned around again and knelt beside the bed. I put my right hand on her shoulder and shook her hard. After waiting a few seconds I was sure she was out cold. Now I put my left hand on her covered tummy. Feeling the silky leotard against my skin, and her tummy slowly rising and falling with her breathing, I felt like I was in heaven. I gently moved my hand around her tummy, felling her flat belly moving, but yet it still felt so soft. I slowly moved my hand up and over her tiny breasts. They were little more than lumps in her leotard. Only sticking up a half inch, but for some reason this just turned me on even more. I softly squeezed them and massaged them for a couple of minutes.
Now confident Lauren wouldn’t wake up I got up, using both hands I pulled her legs around so she was lying with her hips on the edge of the bed and her legs hanging off. I was super please to find that her leotard was soaking wet between her legs. Her juices from her orgasm had soaked into it nicely, also meaning that I could blow into the crotch of them and she wouldn’t know. At this stage I knew I could play inside her and then leave me load in her leotard and no one would know.
I now stripped myself naked. I was standing next her bed, in front of her slightly open legs, doubting myself and trying to tell myself to leave. I couldn’t walk away now.
Using my hands I bent over and lifted her ankles. Lifting them up and resting one on each shoulder. I very slowly hooked my fingers into the side of the leotards crotch and moved it to the side, revealing her very tiny pussy to me. I was surprised how tiny it was. Seeing it up close and personal, I was convinced I needed to feel her. Taking hold of her hips, I could almost wrap my hands all the way around she was so small, I lifted her off the bad till her slit was lined up with my cock. Stepping forward I moved so I had my head resting against her opening. Between her juices already there and my pre cum leaking, her entrance was cover in natural lube very quickly and easily. Holding her tight I gently pushed my hips forward. At first nothing happened, then with another firm push my head slid into her pussy.
My god it was tight, it felt like my cock had just been crushed inside a vice. I waited till her vagina adjusted to me being inside and then pushed again. Happily I got no reaction from Lauren, but my cock slid another inch inside. I knew I was going to have trouble getting in her all the way, knowing I have about 2 inches in and another 7 to go. Another thrust in and I sink in 2 more inches. I slowly start pumping my hips forward while holding hers tightly still. 4, 5, 6 inches slide into her tiny body and I can feel my head pressing into the top of her pussy. I start to slide out and then when almost out push back in, bumping into the bottom of her pussy. I keep this going till I’m sliding nicely inside her and her vagina has adjusted to fitting my huge cock inside.
My next challenge is now to get my remaining 3 inches inside her as I want to feel myself balls deep in her pussy. I start to thrust my cock hard and sharp into her, while also pulling her his into me. I can feel myself stretching her insides as another inch pushes insides. Her juices were flowing wonderfully and coating my cock nicely, helping me push even further into her. My pre cum was already starting to fill her pussy, also making is easier for me to keep pushing deeper.
I felt my cock head suddenly slide in deeper than before. I stopped right then, realising that I had just pushed into her cervix, with my head now plugged tightly into her tube. I give a final hard thrust forward and pull her hips into my crotch hard, sinking my final inch into her body. I now have my 9 inches buried inside my 13 year old tiny sister. I couldn’t believe I had managed to get all 9 inches into her tiny little underage body. I could feel my balls rubbing against the silky leotard over her butt, and could also feel that about 2 inches of my cock was very tightly plugged into her cervix, meaning that my opening was pointing right into her womb. I knew I could only stay like this for a short time before I had to pull out.
Gently and slowly I start to push my hips forward into her over and over, making sure not to pull out any as I wanted to feel her tightest insides for as long as I could. Thrusting forward with each movement of my hips I began to speed up as I could feel my balls starting to tighten. I planned on pulling out and blowing my load all over her pussy and then letting it soak into her leotard so the evidence would be gone. But the closer I got the more I realised that knowing she was in her most fertile time of month and that I could impregnate her and she wouldn’t even know it, I couldn’t bring myself to withdraw.
Thrusting deep into her cervix, with my balls rubbing against her silky cover ass, was all I could take. Holding her hips even tighter, I gave a final thrust in and stopped, my cock clearly pushing against the inside of her belly, which I could see was lumping up her normally flat tummy and stretching against her leotard.
With a loud moan, my cock pulses and cum begins to flow. My sperm races up my shaft and exits into hers, load after load leaving me and entering her. With so much pressure in her cervix and my loads still pumping, my sperm break through her inner sanctum and start to flood into her underage womb, flowing hard and fast inside her belly. I could even see the pulses against her tummy and leotard as each spurt of my seed left my cockhead and entered her insides.
8, 9 ,10 loads of sperm flow down my shaft, then just as I’m finishing my final spurt, Lauren moves, causing her tummy to tighten around my cock, again bringing me to another orgasm of my own. Just like the first time I feel my cock fatten up again as a fresh new batch of baby making sperm races towards freedom inside Lauren. Only this time Laurens womb is already open and 3 quarters full of sperm, so as my load ejects into her cervix and down into her womb her belly starts to swell with the pressure building inside. I can again see each wave of cum as it rises under her leotard and tummy as it flows into her body. As the final few spurts of semen flow into her womb, I realise I have indeed done the one thing I shouldn’t have.
I have no doubt that Laurens tiny little 13 year body is now impregnated with our baby. Slowly I am shrinking and start to slide out of her cervix. As my cock slide out of her pussy I hold her hips up so my sperm stays nicely inside her body. I didn’t want my seed to rush back out and go to waste. Once my cock was clear I used one hand to gently grab the crotch of her tight little leotard and moved it back over her tiny pussy, pulling her slit closed and tightly sealing my sperm inside her young body.
I slowly lowered Lauren down onto the bed and watched her crotch to see if anything happened. I could see a small wet spot right over her slit, but nothing else seemed to be coming out. Her leotard was firmly holding it all in. Looking Lauren over I could clearly tell her belly was slightly swollen, just enough to stretch the leotard nicely around her middle. I leant forward and put my ear to her belly, then using my hand I gently rested it on her tummy and giggled it around. I was instantly turned on again at the sound of my semen splashing around in her womb while my baby making seed inseminated her fertile young egg.
I pulled Laurens quilt and sheets back and out from under her, gently rolled her into bed and then stopped. I realised I needed to do one more thing, so I grabbed a spare pillow from the spare room and placed it under her hips. This lifted her hips and pussy perfectly so my seed would not run out. I then gently placed the sheets and quilt over her body. I figured she would not wake till morning with all the sleeping pills in her system. I made sure to place the quilt so that when mum and dad checked on her when they get home it won’t be visible that she has her hips up just enough.
I set my alarm for 4 am, knowing I would need to go and get the pillow out before she wakes. At this point I went to bed myself. I didn’t really sleep too well, all I could think about it how great it felt to be inside Laurens very tiny underage 13 year old pussy. I heard my parents arrive home, go and check on Lauren and head to bed themselves. At 3 am I couldn’t wait any longer, I had to go check on Lauren and put the pillow away in the spare room.
Once standing beside Lauren’s bed I softly said her name a few times to see if she woke. I then gave her shoulders a firm shake to see what happened. Once I was certain she was still out and not coming too I pulled the covers back over and revealed her tiny body again. Looking her over, I could see the sequins on her chest glimmering in the soft light coming through her window, and looking down a bit further I could see her tummy had almost completely gone back down to being nice and tight and flat again. I continued down and could see that her leotard was still damp around her crotch, but some semen was drying around the edges. I guessed that maybe half y load must have leaked out by now.
It was a mistake to stop and look her over as all I could think about now was making sure her tummy was full again. With a care in the world, I again decided to go ahead and fuck my baby sister till I blew inside her.
This time I grabbed her legs and dragged her around till she was hanging half off the bed. But, I rolled her over so that her tight little ass was sticking out and her legs hang down to the floor. I laid her arms by her side and turned her head to the side. I knelt down behind her and slowly put my hands on her ass and squeezed. Her leotard felt lovely again and her cheeks underneath were soft and squishy to play with. After spending 5 minutes just rubbing her butt I decided it was time. I again hooked her crotch and pulled the still damp white leotard to the side. Without stopping I opened her legs as wide as I could and moved myself forward and placed my cock head at her entrance once again. Putting my hands firmly around her tiny hips I pulled her back as I thrust forward into her body. With so much cum still inside her, I slid in easier this time. She was still like a vice, but it seemed her body as more open for the intrusion.
I drove in till I felt my cock hit the bottom of her pussy again. This time though, I only had about 4.5 inches inside her. With her belly resting on the bed and her body bent over I was going to be able to drive much deeper into her body. I was already in heaven, having my cock tightly resting inside my sister was amazing. Holding her firmly I slowly started to pump in and out of her vagina. Pushing in a little harder with each go, making sure to drive a bit more of my cock inside each time, I began to speed up. Pushing my hips into her harder with every thrust, I knew I wouldn’t last long again this time.
Then without warning my cock head found it’s way home. With a huge push forward I sank another 2.5 inches in, sliding tightly into her cervix again. Only this time I still had 2 inches not inside Lauren. I needed to be fully inside, I wouldn’t accept anything less. I stopped pulling out and began to thrust in only. My cock felt like it was going to be crushed, but I couldn’t stop. Again, after a few minutes of this I felt myself slid in till my balls were resting against her crotch. 9 inches deep and my cock was tightly plugged deep into her cervix. Actually, I put my hand under her belly and I can feel the lump in her tummy where my head was pushing against her. I wasn’t too sure, but I could have made it into her womb completely.
Just the thought was enough, and for the second time tonight my balls went tight, I felt my shaft go even more rigid and then it happened. My semen raced down my 9 inches and blew hard and fast out into Lauren’s baby womb. With my balls pulsing and my cock pumping I unloaded deep into Lauren’s belly, with no doubt I was pumping directly into her womb. While I was unloading inside I felt Lauren’s vagina tense up, and her whole body went hard as she began to orgasm in her sleep. Her tiny body was responding to my cock rubbing her clit. The firmness around my cock just drove me to keep cumming inside her. I couldn’t stop as more loads flowed down my penis to find a new home.
What I hadn’t realised is that while I could feel each load of sperm leaving me and entering her with my hand under her tummy, I couldn’t see her tummy. Because she was still pretty full of sperm form earlier that night I was overloading her womb. Her belly was swelling hugely and stretching very tightly around the middle. Her leotard was now stretching around her belly as well. Only I just kept on pumping, even after realising this.
After about 22 or 23 loads of baby seed were pumped into her tiny womb I came to a stop. As I gently withdrew my cock from her belly and slid out of her pussy, I lifted her up and rolled her body over. I held her hips up as I stood, again so her body would hold my sperm inside. Using one hand to hold her hips up, I used the other to pull her white leotard crotch back over her pussy once again. Only this time because her belly was swollen so much the crotch was much tighter over her pussy. This was a good thing as to hold that much seed inside was going to need a tight plug.
As I lay her down flat on the bed I could now see fully how much damage I had done. Her belly was more than slightly bulged, it was 3 or 4 inches rounder then before I started and her leotard was clearly stretching the material to go around her now. Even seeing this is was still so pleased with my work. My very tiny and young little sister was housing every last one of my sperm inside her belly, letting them play with her fertile baby egg and inseminate her tiny body with our baby.
I could see that my seed was slowly starting to leak back out into the gusset of her leotard, creating a rounded mount over her pussy and down to her ass. The white shiny material was getting wetter and wetter as I watched. All I could do was put her back around into bed and cover her over again. Take the pillow out and put it back in the spare room.
I got back into bed and hoped her belly would be smaller again by morning. I didn’t want mum and dad knowing something was wrong, and Lauren wouldn’t understand. She would probably think she was feeling sick and sore, not knowing herself that I have planted a baby inside her tiny womb for her to grow. By the time she or mum and dad worked it out it would be too late to stop it. My tiny baby sister would be having my baby in 9 months. I would make sure of this by setting it up to fuck her again over the next few nights, making sure to fill her womb with as much sperm as I can leave inside.