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.
