It Just Sorta Happened

All characters are 18yo and up.

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Marissa had moved back home for the summer.

Big whoop. It's not like it hadn't happened before.

She's my big sister, you see. She just wrapped up her last year of college; got a liberal arts degree from the state university I'd be attending next fall-- we'd all gone to her graduation a month ago. Apparently when Uncle Frank asked her at dinner that evening whether she would pursue a graduate degree in her field (Anthropology), that was the first she'd seriously considered the prospect.

She's not an airhead or anything, though her blond locks and meticulously well-kept wardrobe might lend you to believe otherwise... In fact, my mom, my dad, and I all gave her major kudos when she had decided to leave her sorority one semester into her sophomore year. She'd explained at the time that it was a matter both of disgusting internal politics as well as interference with her studies.

From the brief visits we had with her the last couple years, she enjoyed a far more comfortable lifestyle with the friends she split a house with her last two years off campus.

But now she'd moved back home.

Honestly I had missed her!... But it really hadn't been that bad being the only kid under the roof. Mom and dad both started catching a bit of premature empty nest syndrome after their prized oldest daughter had moved out, so they both started doting on me a bit more, and giving me Way more leeway to enjoy my high school career than they had given her.

And since they both worked hard on their careers, I wound up with a pretty comfortable reign over the house most of the time. Seeing as how Marissa hadn't been home for the last two summers, I kind of expected to have an unchallenged rule over the family manor the summer after my high school graduation... But not so.

Because Marissa had moved back home after all.

Her housemates all went their separate ways, and Marissa, my prissy, apple-of-our-parents'-eyes sister, hadn't made any plans after graduating with a degree. So she moved back into her old room, despite the fact that Mom had turned it into her office.

Since my dad was out of town on a retreat, and mom was busy working on a case 12 hours a day, guess who got to move mom's office sofa out, and Marissa's day-bed in. That's right-- yours truly. I practically broke a toe trying to handle the furniture on my own, but there you go.

I shouldn't have been so fed up with the situation, but my first (and so far only) girlfriend broke up with me back over spring break, and I'd wound up quite stag for the rest of the school year, including Prom. Not to my benefit, either... Apparently my ex spread some sort of rumour about me having a small cock. I don't know, I break 7 inches, but I didn't really care about that part of it... I just thought we had something more than that sort of interest in each other. I know it sounds sappy, but she'd been really special to me, and for her to turn that leaf... it just opens your eyes to what people can be like is all, I guess. Especially when it came out after graduation that she'd been seeing someone behind my back the last couple months we were together.

So from making out with my first gf, copping feels, the occasional handy, to a bitter break-up, I'd been pretty sexually repressed the last few months.

The winds of change had begun to blow, though: I graduated with top marks and a letter of acceptance to the state university; no need to get a summer job, thanks to the scholarship coming my way; and mom & dad were going to leave me with free run over the house all summer! I was finally starting to get hard thinking about other chicks again, scrolling my various feeds, thinking about who I might be able to hook up with this summer.

Except for one problem: Marissa.

I couldn't invite any of my buddies over, because of how All of them swooned around her.

And I couldn't bring any of my female friends or romantic prospects over because of a... finer problem.

Marissa had taken to lounging dead center in our family room for most of the day, most every day for the last week and a half. Wearing a series of various silk nighties. And Only that nighty. Nighties that seemed practically like lingerie, except for the fact that none of them consistently shielded her lower bits from view. The only times she maintained a sense of modesty, in fact, were when mom or dad were home... which again, were infrequent.

Damn was the whole situation pissing me off!

Nearly two weeks into summer, and I'd been trapped in my room for WAY too many hours out of any given day! Sure, I'd been able to get out a couple times and bike out to the beach or my buddy's pool, but I'm sure you can imagine how embarrassing (not to mention inconvenient) it is to have to bike around town as a fresh graduate.

I couldn't bring myself to have my buddies over to leer at my sister, and the lack of an income or car made macking on the ladies a lot more difficult than expected.

That left sequestering myself in my room, or hanging around the house with Marissa, which I was finally pent up enough to start broaching again, sisterly-modesty-be-damned.

We hadn't said too much to each other since she moved back in to find her bedroom prepared for her: the typical "I'm glad to see you again bro/sis!" expected when one comes back home; asking about each other's plans for the summer, just to discover neither had any; and the regular "good morning bro/sis" as we ran into each other whenever either of us made it down to the kitchen for brunch.

Half of why I didn't pursue too much conversation with her since summer'd begun was my being prickly about losing control over my summer castle. The other half was her lady bits.

I don't know what I was expecting back on the 2nd day of summer as I was sitting at the kitchen table, scrolling through my insta feed, munching my way through another spoonful of fruity pebbles, but my sister's red and blue silk nighty caught my eyes as she glided in. We traded our 'good mornings', and my eyes practically bulged from my head when I noticed her reach up to the high shelf for a cereal bowl-- her round, firm butt cheeks were on full display. I didn't even bother putting my bowl in the sink before rushing back upstairs to my bedroom. My dick was suddenly raging, but there was NO way I was about to jerk my first load in months to my Own Sister. Vomit! Right...?

Several more similar instances occurred in the following days, from mid-morning to the early afternoon. My eyes and my teenage imagination couldn't seem to escape my big sister's body parts: her ivory, round ass cheeks, with that little trio of freckles on the lower cusp of her left cheek; her supple, round tits that always seemed on the verge of slipping around the silk hem of her next nighty; her forbidden little pussy lips that I was Sure would be there waiting for me if I were ever to let my gaze venture in that direction...

But, No! My pride, my intellect, my conscience wouldn't let my imagination run with whatever images they came across. It was a vicious internal battle raging in my head that first week and a half. It was even starting to get difficult to tell whether they were real memories of big sister's lady bits, or just my taboo wonderings and imaginings.

Day eleven of summer, the resistance front collapsed.

I got up first, mid-morning, and made a bowl of cereal. I was sitting on the living room carpet, wearing nothing but the athletic shorts I'd slept in, propped up against the couch, so that I could place the bowl on the coffee table whenever I used the remote to skip past the intros of the series I was going to binge.

I noticed Marissa breeze down the stairs out of the corner of my eye. Apparently she liked my choice of breakfast, because she plopped into the couch behind me with a bowl of her own.

"Morning, bro," as she began into her bowl.

I turned my head to say, "Morning, Mariss--!!"

That last came out as an explosion of milk and cereal into my windpipe and out my mouth & nose.

Because Marissa's puffy, vaginal lips were a foot and a half from my face, and those sisterly vaginal lips were (thanks to the way her legs were half cross-legged) gaping slightly open, a slight moisture glistening on the edges. It was almost like my sister's flushed vagina was staring right at me-- her younger brother! WTH!?

Marissa nearly spilled her own bowl of cereal jerking back from my milk-coughing reaction.

"Oh my god, Jake! What happened, are you okay?!" she half-yelled, half-laughed, putting her bowl on the coffee table and patting my back.

"Ergghuh!" I coughed, finally clearing my throat, turning back to face the tv. "I'm fine, I'm fine, sis, sorry, thanks."

"Are you sure?" she pressed, sitting back into the couch.

"Yeah, no I just accidentally saw your, uhmm..." I started blushing, clamming up.

"Oh geez, that's right. Sorry bro, I hope it doesn't bother you-- it's just something me and my roommates have gotten used to the last couple years," Marissa laughed off, lightly.

"You guys just all hung around the house naked?"

"Not naked, bro. Well except for Meghan, sometimes, or Denise here & there. Just, ya know, comfortable." She was smiling-- I could hear it in her tone, even though I was resolutely keeping my eyes on the tv in front of us. "It's healthy to be comfortable in your own skin, and especially healthy to be comfortable in your own home. Lowers stress levels over time, promotes longer life-spans and fewer wrinkles, you know," she said, as though she were giving a textbook lesson.

"Uh huh," I replied, trying my best to figure out what the most appropriate way to respond to seeing my big sister's pussy lips, and her casual acceptance of the same.

Did she really think this would be okay with me? I'm her brother! She's my SISTER! GROSS! Right??... Except my dick is definitely sporting a raging hard-on right now...! WTH-- this was So Fucked Up!

And then my shoulder devil whispered into my ear.

She thinks this should be okay. Being comfortable in your own skin, in your own home. Is she really that wrong? I mean, what was I really upset about before, if not being able to do the same until she moved back in. Maybe big sis was right.

But as I tilted my head to reply to her, the little brother in me who'd always looked up to his big sis, wouldn't let me turn to look right at her pussy again. "You're right. I guess I didn't think of it that way, sis."

"No one does, bro, until they do," she chirped back with pep. "But I guess, I can't blame you for coughing up half your cereal-- not everyone expects an eye-full of their sister's pussy for breakfast!" She began laughing again.

I laughed along slightly nervously, "I guess it's not as bad as a mouthful!" wondering if that was the right response. Her fit of laughter doubled up, putting me at ease. I joined in, turning to see she was actually clutching her gut, laughing. Her legs actually blocked my view of all of her lower parts, but somehow this was nicer than the more explicit look I'd gotten before-- the big sis I'd always joked with growing up, was back on the family couch, laughing at one of my jokes. And damn if she really wasn't a grade-A babe.

I don't know how I hadn't really let myself notice it before. Marissa could be one of those Onlyfans models making beaucoup bucks with strip teases, or a fashion model on the fronts of magazines if she wanted to. She kept herself in firm, petite shape with almost no effort, had a natural sense of style, and she had that blonde hair-green eyes combination that drove me nuts like no porn star could.

And here she was, right in front of me, busting a gut to one of her little brother's jokes.

My hands leapt for her sides just like old times, before she'd left for college. My fingers knew exactly where to find her old ticklish spots.

Marissa shrieked as she realized the tickle fight was on!

My fingers, at first attacking her ribs over the silk nighty found themselves between the fabric and her bareskin as our rough-and-tumble battle moved from one corner of the couch to the other.

"OH MY GAWD, JAKE!" Marissa laughed as she tried fending off my tickle-assault with her elbows and legs.

It was probably on accident, but she kicked me right in the jaw, and before I could think straight, wrapped her legs around my torso, pulling me onto the couch with her.

"Your Turn, Little Brother!!" She laughed confidently as she twisted on top of me. One of her straps had fallen off her shoulder, threatening to reveal one of her pert little B-cups, but before I had a chance to wonder further, her nimble little fingers began tickling my own exposed sides.

It was a lot like old times, finding myself suddenly victim to my older sister dominating me in a tickle fight-- I couldn't quite stop her from tickling one of my exposed spots before she found the next one, and unfortunately, I was just as ticklish as she was.

I kept trying to inch backwards on the couch to get out from under her bodyweight, but she was doing too well at keeping her legs half wrapped around my hips. Maybe that was the reason, or maybe, it was me trying to inch back on the couch to get away from her, but my shorts slipped past my hips before I even noticed they were a problem.

Marissa was way too keen to keep the advantage in our tickle fight to notice my exposed member and kept lifting & inching her leg-locked hips up my own until--

-POP-

We both looked down at where our hips met.

There hadn't actually been a literal Popping noise-- but there may as well have been: my little brother dick was almost completely ensconced in my big sister's pussy. There was maybe an inch and a half of me still not quite lodged in Marissa's cunt... kind of moot in the grander scheme of things.

Marissa looked up at me, her mouth half agape, face flushed, tears welling up in her eyes. I'm sure the look on my face must've been similar. Except I wasn't about to cry.

"ohmygod, Sis!" I whisper-shouted! I started to lift my left hand to her chest to help push her backwards, off her brother's cock, but she caught my hand in hers.

"Shit-Jake! D-d-don't move, please!" she whimpered, nearly squeezing her eyes shut. I couldn't tell if it was pain or pleasure or anger or disgust in her voice, but she was clearly shocked.

My eyes darted back to where our siblings parts were joined. I was inside my sister's pussy! My dick was inside an actual vagina for the first time-- and it was my SISTER'S!

That fact was blaring at maximum volume in my head as I glanced back at the illicit bonding taking place at our crotches. So much so that I almost didn't notice the blood starting to show around her netherlips, on my shaft.

Blood! My mind was worried about a whole new crisis for a moment before I put two-and-two together.

"Ohmygawd sis, are you okay! You're not a virgin also, are you? I thought, I thought that--"

"Shut Up, bro, oh-my-gawd-this-is-soooo-Wrong!" She half whimpered at me, finally looking me right in the eyes again, biting her lip. "I fooled around a fair amount in college doing other stuff, but never actually... well.. it doesn't really matter at this point..." she sniffled. She dropped her gaze, and I felt what must've been a couple tear drops land on my abs.

Shit-- I had accidentally taken my sister's virginity. What the actual Fuck. While losing my own?! This was SO Messed up! And yet my cock was raging harder than it had Ever been! I was sporting my most massive hard-on ever, even though I could literally see my big sister's hymen blood around my shaft... This was going to take So much therapy.

Time seemed to slow down to a halt as we both remained motionless on the family couch. My show droned on in the background, unheard. Both of us were breathing and trying to figure out what our bodies were supposed to do in this predicament.

With one last sniffle, my sister lifted her gaze to lock eyes with me again.

"Jakey, th- this is so Bad, what's happening right now!" she said, urgency behind her words.

"I know, sis! I'm-So-Sorry-it-was-a-Complete-accident-I-SWEAR!" I rattled off in a nervous flurry.

"Me too!" She interrupted. "We, we need to, uhh..." her voice trailed off, as I felt her vaginal walls undulate up and around my shaft.

I'd never felt something so perfect.

I knew my dick felt good when I was beating off, or when my ex would lend a hand, but How can you explain the first time you feel a vagina mould itself around your cock, and ripple its pleasure into your own.

I almost came right there! Inside my own sister's pussy. It wasn't even the thought of our incest that stopped me-- it was some deeper imperative to not cum before my partner.

As it was, I definitely felt a half-load of precum churn out of my shaft. 'Shit! Can precum get a girl pregnant?' my shoulder angel tried shouting.

My big sister leaned forward and locked her mouth around my own in a passionate full-on makeout kiss before I knew what was happening.

I was definitely kissing the woman on top of me back with a fiery passion! My hands suddenly clasped behind her, our mouths our lips our tongues intertwining and parting only for a moment as I wrenched her nighty up and over her head only for our lips to realign into each other angrily. Who was this passionate succubus mounted atop me??

'YOUR SISTER!!' My conscience shouted back to my hormone-addled libido.

I pulled my face back from my sister's, wide-eyed. She was panting, huffing as badly as I was, her face flushed and splotchy. Emotions raced across her eyes, her cheeks, the corners of her mouth.

"UgghhhHH!" she moaned, as her vagina rippled around me again, and then again, and again upwards more rapidly! Marissa's back arched dramatically, her head thrown back so violently that I felt her long hair hit my legs.

'Your sister is cumming on your dick,' the back of my head noted absently.

I was able to start getting a hold of my breathing, and start organizing my thoughts as Marissa began to come down from her orgasm.

And then I realised how pristinely hard my shaft was. It was twitching inside big sis.

She was definitely spasming around me, simultaneously. But my cock was twitching, and I was fairly positive it was because I was in danger of blowing.

In danger. In danger? How could there be danger right now, when my body felt Better than it ever had??

Sister! The cunt you're inside is your big sister's! Your blood-related sister is sitting on top of your shaft!!

Is big sis on the pill?!

"Sis! Marissa!! Are-are-are you on the p-p-pill?!" I stammered, trying not to let my perverted thoughts get away from me.

Her hands dashed from my shoulders (when did they get there??) to my face.

"No, I'm not! And Jakey! You CAN'T cum inside of me right now-- this is a Really bad time of month for me!!" she pleaded, locking her green eyes onto my own.

I don't know what other choice I had-- I knew she was right. She was DEFINITELY right! Brothers DON'T cum inside of their sisters.

"I love you, sis," I told her, our eyes still locked.

"I love you more, little brother," she whispered, her pussy clinching when she said brother.

And that's when I came inside of her, my eyes and mouth widening into a silent gasp.

Her pussy began clinching again desperately a slit-second into my own ejaculation. "No, no, noooOO!--AHHH-YESSS!"she screamed up to the living room ceiling again, before looking down at her little brother, mounted below her.

My shaft surrrrrged jet after jet of virile jizz into my older sister's fertile vagina. It was hard to tell how long our orgasms took... was it minutes or an hour? My breath started coming back into my focus. Marissa was still perched atop me, but leaning back onto her propped up arms. I noticed my shaft was softening rapidly, and Marissa's vagina had stopped pulsing so much.