Accidents and not-so Accidents

Disclaimer: All acts and characters are not based on real people.

I learned two things about my sister-in-law, that changed my life. Thing one: She often goes without panties throughout the day. Thing two: She has no feeling in her pussy. Now you might be asking, "Peter, what the fuck?" I don't know the explanation for that, and frankly, I don't care either. Let me set the scene for you.

First, I am happily married. My wife, Susan, who is 28, is also the breadwinner of the family (the two of us), easily making upwards of 200k a year as an accountant. The tradeoff of the pay is that she goes on business trips across the country for months at a time for big companies. However, every night at 8pm my time, she calls and tells me about her day. Her skin is pale, and her hair is curly. She has breasts as big as my head and is a very warm and caring person. Susan is also very smart, way smarter than me.

My job is essentially a handyman for a nearby senior living complex that pays well and isn't very physically demanding, however it does demand me being there for any late-night issues that may happen, such as an AC unit fucking up, or something of that nature. So, I stay home, while she gets the big bucks.

Her sister, Mia, is near the opposite of her sister. Aged at 19 years old, she is tanned, with straight long hair. Her breasts are five times smaller than Susan's, but her ass is like two melons side by side. While Susan is way smarter than me, I am way smarter than Mia. With as much love for her as platonically possible, she's a fucking idiot. However, the few brain cells she has are absolutely developed towards cooking. In fact, it's the reason she stays at my and Susan's home while Susan is away. My idea of a meal is a quick-frozen dinner, and Susan doesn't like that.

So, now that you know the basics, let me set the stage of how I found out about my sister-in-law. It's been two weeks since Susan has gone to Seattle for her job. At best, she would be back in four more weeks. Mia was off in her room, on the phone with her boyfriend, Todd. I finally had some "me" time, so I sat on the couch, and put on some YouTube documentary. Shortly after it started, my mind began to wonder, and I felt an urge to masturbate. Mia's phone calls took a while, so I should have plenty of time to rub one out before she would leave her room.

I get my cock out and go to work. A few minutes later, I am getting closer to the end when I hear a noise. I open my eyes to investigate, and as I do I hear, "Oh hey!" And before I could react in a desperate attempt to hide my dick, Mia had leaped over the large arm rest. Time seems to slow as I see her skirt flutter up and take panic noticed of her fat naked ass in front of my face. And as if some deity was invested in my life, my fully erect cock that dripped with precum was forcefully enveloped by Mia's unaroused pussy. I felt the head of my penis slam almost painfully against her womb. The sudden sensation around me was too much, and I erupted. Within the span of two to three seconds, I went from masturbating, to cheating on my wife by cumming balls deep into her sister's pussy.

I could barely enjoy my climax, as my mind went into overdrive. I was expecting her to immediately flip out and start screaming or hitting, but it never happened. Mia glanced back at me for a moment. "You know I love Minecraft builds! You could have waited for me!" It took me a second to recognize what she was talking about. The video I put on earlier had changed, an autoplay of some guy building a castle in the mountains. She leaned forward a bit, giving me a fantastic view of her ass and my cock buried inside of her, to get the remote. She sat back, shoving my cock deeper inside her pussy, and turned the video up more. Every once in a while, she would squirm when something she found cool or exciting would happen on the video, and the motion would keep me erect.

Not once did she say anything about my cock in her. And she definitely wasn't acting like she meant for me to be inside her. That's when I realized she had no feeling in her pussy. I felt a sigh of relief escape me. This was indeed an accident that happened, and no one was going to get in any trouble or anything. There was a momentary flicker of panic about the fact that I came deep inside her without having cum in a few days, so it was a big load being blasted into her womb, however the panic dissolved into lust. I did have a breeding kink, and the thought of this one accidental creampie being enough to knock up my sister-in-law made my focus return to my own pleasure.

The gentle movements she made was great stimulation, and every once in a while, the video would cut to gameplay that would make her tense up in anticipation, where she would unknowingly milk my cock. She started doing small bounces when the video started showing organizing different chests. I could feel another climax approaching when whatever deity was timing things acted up again. Mia glanced back at me and did a violence bounce in my lap to unknowingly slam my cock against her womb and said, "Fill her up with your seed!" The words broke the dam I was holding back, and for the second time in ten minutes, came deep in Mia's pussy. She giggled as she pointed at the screen of the in-game chest full of farm seeds. I let out a breath of air that sounded like a soft laugh, and she turned back around to continue watching the video. The video eventually ended a few minutes later, and she slowly got up. I quickly hid my penis back under my sweatpants, but took notice of something that stirred arousal in me again. As Mia got up, no cum dripped out of her. A quick check also showed that my own cock was only moderately damp, not wet with cum.

With a smile, she bent back down to kiss me on the cheek, and the moment her lips pressed against me, I came to the realization that her womb has absorbed all my cum. I felt my cock stir at the idea. As she stood back up, Mia left out a soft gasp. "Oh! Um... Peter?" She pointed down to my semi-hard cock slowly growing in my sweats. If this was an hour ago, I would have tried to hide my dick away from her. However, having just came in her twice, I felt no immediate desire to do so. I still needed to explain it away though.

"Sorry, Mia." I tried to sound sheepish. "It's been a few weeks since me and Susan... you know. And having a girl as pretty as you sit on my lap for a bit while backed up would definitely cause 'him' to act up."

Mia's tanned face blushed a light red. "I-I caused that?" She asked as my cock got fully erect, tenting my sweats.

"Yeah, I'm sorry Mia, this is so embarrassing." I played the gentleman that she thought I was, instead of the pervert that just came in her unfeeling pussy twice. Mia's face grew redder.

"D-don't be embarrassed! I mean, you should be proud! W-with the tent you have, y-you must be really b-big." She stared directly at my bulge. "A-and without S-susan here, your balls must be full." Her eyes widened. "Wait, that's really bad! If you get blue balls, you'll get sick!"

At most I'll be in discomfort, but she seems concerned. I could ease her worries... but I could also use this. "I will?"

She nodded vigorously, finally turning to look at my face. "Yes! And then if you get sick, then Susan will get sick too!"

"That's bad." I murmur with as much concern as I can.

Mia ran her hand through her hair and thought for a few seconds. "Wait! I have an idea!"

My cock twitched. "Oh?"

She looked worried for a moment. "It's not cheating if we both aren't conscious!"

Huh? "What?"

"Look, so I'm with Todd, and You're with Susan. So, either of us doing anything would be cheating! However, if we were to sleep naked, with your cock against my ass, there's a good chance that in your sleep, you'll slip inside! It's a win-win! Your balls are drained, so you won't have blue balls, it'll be my ass, so I won't get pregnant, and we'll both be asleep, so we aren't actively cheating!" She put her hands on her hips and had a proud look on her face. I won't turn down a good time, and I can pretend to fall asleep so I can have my way with both her holes. Also, this is the most I've seen her think in a long time, so maybe she deserves some praise.

"Damn, Mia! That's a good idea! You're so smart!"

The bright smile on her face left a good feeling in my chest.

"I know! And don't you worry, I'll get those balls of yours drained!" With her proud statement, her phone buzzed. "Oh! I forgot; I have a date with Todd. I'll be back, okay Peter?" and she left, leaving me in a daze of lust and guilt.

Later that night, Mia walked back in from her date with Todd. Her top was inside out, so it probably meant she got fucked by her boyfriend. She did look a little ashamed and upset when she came up to me. "Hey Pete, can you... set an alarm for me in the morning? I need to go to CVS, and they closed as soon as I got there."

"Plan B?" I asked.

"Plan B." She nodded.

I get up from the dining table, where I just finished eating some storebought Salisbury steak. "Don't bother, Susan has a stock." With a questioning look on her face, I take her to my and Susan's bedroom, where I open her bedside table drawer. Inside is a row of water bottles, and several packages of the medicine. She made a questioning face as she looked at me. I explained, "I have a breeding kink. However, we don't want kids right now, so..." I gesture to the medicine.

"Kids..." She trailed off. "Maybe I'd like to have kids with Todd..."

"Well, if you don't want to take 'em, you don't have to. But they're here." I offered. She nodded and gave me a hug.

"Thanks Pete. I'm barely awake on my feet, so, are you ready to get your balls drained? She smiled.

"I appreciate this, Mia. I've been thinking about this all night." I tell her. Mia blushes.

"Well, I can't let you get sick, after all, bro." With that said, she begins to strip. Her tanned body looks great, with her smaller breasts, subtle abs and birthing hips. I stare at her pussy for a few moments, thinking back on how I came balls deep in her twice today. "Ah ah" she said, lifting my chin with one finger to look in her eyes. "I'm ovulating now, and I can't have your stored up cum overpowering Todd's." As she says this, a voice in my head just repeats 'knock her up, knock her up, knock her up'. Another thought appears. 'Mia's ovulating? And I came in her twice? I probably did knock her up.' She slowly turns around and presents her large ass. Mia bends, and tantalizing spreads her fat cheeks, showing off her tight clean asshole. "Here's where you will unconsciously have your fat balls drained, okay?" Mia looks back over her shoulder with a wink. My erect cock twitches violently, so violently it ends up removing my sweats.

Mia gasps. "Holy shit... Pete... I don't think it can fit in there. You're... way bigger than Todd."

Her statement causes my cock to throb harder. "It looks like it'll fit fine. Here, I'll show you." I take a step towards her, and the head of my cock is now gently pressing on her asshole.

"Wait!" Her voice sounds panicked, and I can see her asshole clench. "If... if we're awake it's cheating. I-I don't want to be a cheater, Pete."

"My cock isn't going to enter your asshole while you are awake Mia. I'm just sizing it up. Where's my... aha here it is!" I lean forward, actively pressing my raging cock against her tiny asshole. Just as I feel her ass about to give way, I grab my phone and stop pressing into her. I access the camera and take a picture of my cockhead resting against her hole. Then I press into her again, showing her the picture as an excuse.

She gulps and I feel her anus twitch as if it's about to open again and remove my pressure against it. "Y-your dick is... three times the size of Todd's... I.... I... I'm putting my faith in you, Pete." Mia stood up, turned around, and hugged me, my erect cock poking into her stomach. She gazed up at me worriedly. "Please try not to hurt me."

I felt the overwhelming lust circling my brain clear out. "Hurt you?" I returned her embrace. "What do you mean?"

Mia nodded. "Your cock is huge... I was all for draining your balls, because I don't want you to get sick. But, you're too big. I'm worried that in your sleep, your instincts will take over and you'll plow me super hard. Your dry penis ravaging my dry asshole will only hurt us both."

On one hand, I was annoyed at this prevention, but on the otherhand I felt concern. Regardless of me pumping two loads into her earlier, she's still my sister-in-law that I've known for years. The least I can do is try to ease her worries. "I understand your worried. I'll speak facts outloud so we can think this through together. If you are still set on draining me so I don't get sick, it would require one of your three holes. Correct?"

She nodded. "Yes. You need all the semen in your balls out or you'll get sick."

"Okay," I say, trying to ignore her reasoning. "and since you're ovulating, if I cum in your pussy, I'll overpower Todd's semen trying to impregnate you at this moment. Correct?"

Mia blushed at the bluntness. "Y-yes, you have two weeks of cum in your balls, that'll definitely knock me up."

My cock twitched against her stomach at the thought, and the reminder of her womb practically acting like a sponge earlier to the two separate loads I shot in her. "So that leaves two other holes. Your mouth, and your ass. Correct?"

"Yes."

"So the concern is, that with both of us asleep, my cock will hurt your ass. The other concern, is that if I use your mouth while we're both asleep, there's a chance you could choke and die." Mia's eyes widened in concern.

"I didn't think of that! My throat definitely can't fit your girth!"

"That leaves only your ass. So, if we're both asleep, you're concerned that my instincts will end up my cock hurting your asshole. Correct?"

Mia nods again. "Yes."

"So, if you want to make sure that my balls get drained so I don't get sick, and you don't get hurt from both of us being asleep, that leaves a total of three options. Option one: my balls don't get drained, and we risk me getting si-"

"Not that one! I'd never forgive myself if you got sick!" Mia interrupted.

"Okay. Option two: We both sleep anyway, and hope you don't get hurt."

Mia made an uncomfortable face. "And the third option?"

"Option three: One of us is awake."

"B-but that's cheating!" Now time to work my silver tongue.

"I understand Mia. But, what if it's an accident?"

"Huh?"

I bend her over the bed again. "So let's say, you're asleep. Then, after a few drinks, I come to bed. In my drunken stupor, I see a naked ass in bed. Thinking the ass belongs to Susan, I eagerly fuck it. Once done, I go to sleep, wake up thinking I had a wet dream, and you wake up with an ass full of cum. What do you think?"

I gently press the tip of my dick against her anus again as she thinks the idea over. "W-well, the only issue here is, if you're drunk, you might let your instincts take over anyway. W-what if..." She trails off for a second and presses her asshole against my cock. "What if I walk in and see a dildo instead?" Not only is she taking initiative, but also had an idea for 'not cheating'?

"I see. I'll cover myself up with blankets and fall asleep, and you walk in only seeing a 'dildo'. You get to control the pace, to make sure you don't get hurt. I like it! You're so smart, Mia!" Her anus twitches at the praise. With one last press that almost slips in, I go over and lay on the bed, and cover all of me but my penis. "Give it like ten minutes, then come back in!" I call from under the blanket.

"O-okay!" She walks out, and I occasionally stroke myself to keep me erect. After I assume ten minutes, I hear the door creak open again, I close my eyes and pretend to sleep. "A-are you awake?" she whispers out. I refuse to respond. "Asleep... and still so hard." I feel the gentle touch of a finger, that slowly turns to into a hand that softly strokes. "God, how am I gonna fit you in me? You're twice the size of my asshole...." I feel her shifting over me. Is she talking to me? Or just talking to herself? I crack my eyes a bit, to see her straddling over me, one hand guiding me to my destination. I close my eyes, and feel soft flesh touching the tip of my cock. "You almost slipped in me a while ago, you know? I almost let you too. Todd doesn't want anything to do with my ass, but you, bro, your huge cock got hard from it. Do you know how hot it felt, that I could make you hard? You, who has my sexier older sister?" She's now pressing harder against my cock, and as she says the word 'sister', my dickhead pops into her asshole. It takes everything I have not to moan at the warm sucking sensation her anus does to my tip. "Fuck, your huge. I'll have to go slow, or you'll tear my virgin ass up." My cock throbs at her words, which sinks another inch into her. She moans as it does, but then quickly muffles it with her hand. "C-can't have you waking up. I want to experience what my sister gets to feel in her whenever she wants." She stops moving for a second, before she sinks down another two inches of my eight inch cock into her tight warm asshole. "Pete, you lucky bastard. Hard to... catch my breath with this monster inside me." Mia is now actively panting. "Grit your teeth Mia. Get it all in there and then..." Is she trying to take it all at once?

As I think that, she takes a deep breath in, and slams her whole body down. If I wasn't already awake, the force of that would've woken me up for sure. I let out a quiet groan and a pleasurable weak thrust up into her. Mia is now panting heavily. "So... fucking... big...." My cock throbs in her ass, the warmth and tightness of her being fantastic. "You fuck... Susan with this... all the time, huh? Shit." She trails off, before I feel gentle rubbing on the top of my cock. "You're so deep... in me... that you're... bulging my stomach." I crack my eyes open and see in the faint darkness that Mia isn't lying. There is a small bulge in her stomach. And everytime she rubs it, or pokes it, I feel it on my cock.

It's been a few minutes of her getting used to my cock in her now non-virgin ass, and the lust is re-clouding my mind again. Time for her to see proof of those instincts she was worried about. I gently thrust into her, and she moans. "Mmmmm. There're those instincts. Trying desperately to breed. Sorry Pete, you can cum all you like, but no breeding this hole." Slowly, Mia starts bouncing on my cock. Every once in a while, I thrust back into her, and her sphincter tightens around the base of my cock. "Fuuuuuuuck. I should've done this ages ago. Your cock is so good Pete. I'd love to watch you rail Susan some time. That perfect body getting filled by this perfect cock." My cock twitches at the imaginary though of Mia cheering me on as I breed Susan.

"Mmmmmmmmmmmmia" I moan out. Her anus tightens and she begins to ride faster.

"Shit... are you dreaming about me?" She quietly asks, and leans forward as she rides to better hear my purposefully let out mumbles.

"..........ake it...."

"Take it?" Mia whispers in my ear. "I am taking it, Pete. Taking your big hard cock in my tight asshole. You're doing so good for me, baby." Baby? Oh well, whatever helps her.

"breed...."

Her asshole tightens immediately. "You wanna breed me, bro? Put a baby in your sister-in-law? Get your sister pregnant? That's so hot. Empty those balls in me." She moans as she rides as fast as she can. I feel my end coming soon.

"....Mia... get... preg..." I mumble and 'sleepily' grab her hips and slam my cock as hard and deep as I can before I cum deep in her asshole.

Mia gasps. "Fuck I'm cumming! Knock me up!" she whisper yells in my ear as rope after rope of seed fills her ass. Mia's hole tightens almost painfully so, as she moans, experiencing her first anal orgasm. "Good job Pete." She whispers once she's done cumming. "You knocked up your sister." Mia moans and slides my cock out of her ass. "What a naughty dreamer you are. I guess I was essentially teasing you all day." She shifts a bit and groans quietly. "I'm glad you didn't wake up. That'd make us both cheaters." Mia seems to be more honest while I'm 'asleep'. "I don't want to be a cheater. I wonder if you'll let me... use that dildo again." She trails off for a moment. "I could blackmail you, say I'll tell Susan that you were dreaming about knocking me up if you don't let me use your cock again."