The Social Experiment

I was in heaven, but I suddenly noted a curiously mischievous smirk on Abby's face as she studied my cock intently.

I looked down, and noted that the still semi-erect extension was wet and glistening, coated with the combined juices that resulted from our frenzied lovemaking.

"I've never done this before," she whispered, "but there's something about being with you that just brings out the dirtiest side of me."

I watched intently as Abby scooted down my body to my cock, and shot me a devilish glance as she stuck a tongue out and licked the slick shaft.

She kept her eyes glued to mine as she licked the length a few times, then wrapped her lips about the tip of my cock before swallowing my length, and in a slow, deliberate manner.

Abby's head bobbed up and down slowly, as she sucked on me wantonly, savouring every drop of the juices that coated my member.

I groaned into the back of my arms, enjoying the sights along with the sensation of my sister's post-coital oral attention.

My cock was usually sensitive and prone to overstimulation in this state, but Abby was so careful and gentle.

It felt pleasurable in a way that I was entirely unaccustomed to and to my absolute surprise, I began to feel the unusual sensation of another orgasm building deep within my scrotum.

"Abby," I moaned softly, and she shot me a confused look for a moment before realization dawned on her, and I heard her stifled moans as she sucked with increased vigour.

I vaguely noted that she was furiously rubbing herself off as cum began to shoot again out of my cock, and she swallowed every drop, not pausing for even a breath until every drop of my cum was down her throat and on its way to her stomach.

She furrowed her brow, my softening cock slipping from her lips as she focused her attention fullly on rubbing herself off.

"Your cum... it's smeared all over my pussy... it feels so dirty, using it to rub myself like this," she muttered with a moan, and sensing that she was close, I leaned forward to cup her breasts into my hands, pinching her nipples to spur her on.

"Of course it does. Because you're my dirty, slutty sister," I whispered, caressing one breast as I twisted and fondled the other.

"Oh Caleb! Mnh, I'm cumming again!" she moaned, a series of moans coming from her lips as her fingers brought on her third orgasm of the night.

I held her as she collapsed, breathing heavily, at my side, and as she caught her breath I studied her with fascination.

She caught my gaze, then smiled as she crawled her way back to my side, and curled up in my arms, still panting.

"Wow. That was intense. Masturbating is always good, but damn, you have not lived until you've rubbed yourself off using your brother's cum."

I kissed her on the lips with a smile, and as she smiled back at me stupidly, I marvelled at the fact that we were capable of having such a typical sibling moment in the midst of such an unsibling like act.

"By the way, I didn't know that was possible," she muttered, nodding towards my cock, and I nodded my agreement.

Sure, I'd read before that men were capable of multiple orgasms, but I was always so sensitive after cumming that I had firmly believed the phenomenon was nothing more than a myth.

"You must be tired," Abby muttered, and I half-nodded this time, my consciousness slipping as my exhaustion seemed to all at once catch up to me.

"Sleep, my little prince," I heard Abby's voice whisper comfortingly, and I smiled as she kissed me lightly on the forehead as she had so often done when I was little, drifting off to sleep in the blissful comfort of her arms.

***

"Mmh," I woke up with a satisfied stretch.

A bright little sliver of light was filtering through the window across the room, and a soft gentle breeze fluttered occasionally through the curtains, stirring the air in little undulating waves.

My hand reflexively reached to the spot beside me, but the space was empty despite the presence of a lingering warmth.

I rubbed my eyes a bit as my vision adjusted to the soft light, and as I looked away from the window to the little desk that usually stood in the corner of my sister's room, I spotted her, and a smile reflexively crept across my face.

"G' morning," she muttered.

Her voice was timid, and there was a little hint of blush on her cheeks as she sat on her desk chair, her knees drawn up to her chest, and her arms wrapped protectively about them.

"Morning," I mumbled, suddenly noting that a curious space seemed to draw out the distance between us.

Abby was nervous, and so was I.

The deal had been to do what we wanted for a night, hadn't it?

And now that that time had expired...

What now?

Or at least, that's what was probably going through her mind.

"Will you get your silly butt over here?" I asked, and her eyes got a little watery as she nodded, before leaving the chair and heading over to the bed, almost leaping into me.

"I just thought that-"

"I know what you thought, dummy," I chastised her, and she wiped away some tears as I hugged her tight.

She cried a little, and I held her, stroking her hair reassuringly until she calmed down, and she looked up into my eyes, her light brown eyes still shimmering slightly, tinged with uncertainty.

"So you don't regret anything?" she asked, and I shook my head.

"What kind of moron would regret having an amazing night with the woman of his dreams?" I asked, and she blushed again.

"I'm not August Summers, you know," she countered, and I smiled:

"No, but... she does look an awful lot like you, doesn't she? Do you think maybe I was subconsciously drawn to her?"

"Interesting. So she was just my substitute?"

Her eyes momentarily flickered to my lips, and I noted that the atmosphere had again changed, as a little electricity seemed to be flickering to life between us.

"Ah! What're you-?" she yelped as I pulled her over my body and onto her back, before leaning down to kiss her.

I planted a few quick kisses before I suddenly remembered with a lurch that I'd just woke up and probably had some serious morning breath going on, but as I was about to pull back, Abby pulled me down onto her, hungrily returning my kisses with some vigour of her own.

"So we're really doing this, huh?" Abby asked, an excited look in her eyes, and I nodded.

"There's no going back for me at least," I muttered, and she smiled, kissing me again.

As she pulled back, I covered my mouth gingerly, and she rolled her eyes.

"Really? I licked your entire body clean of our combined love juices after you fell asleep last night, I think I can deal with a little morning breath," she chided, and I chuckled a little.

"Still, shower and breakfast?" I asked, and she nodded.

"We still have crepes," she muttered, and I smiled, before climbing out of bed and taking her covers wrapped about me.

"Are you serious?" Abby asked, staring at me with absolute shock and I blushed.

"What?" I asked, "I don't like parading nude. Besides, I told you I. I'm this way even around my girlfriends."

I smiled smugly, but as I started for the door, she charged at me and I saw her move a second too late as I made a dash for the door.

*Whack!

"He-ey!" I complained as she smacked me hard on the butt, then went for my hands, doing her best to wrestle the thin cloth wrapping from my hips.

She was cackling gleefully as she fought with me, and though I complained I was barely able to restrain my own laughter.

I tumbled to the floor, tangled up in a mess of cloth and limbs, and Abby rolled me over, a triumphant expression on her face as my nakedness finally came exposed.

As she grinned over me, I rolled my eyes, then folded my hands.

"What would mom say if she saw you acting like such a brat?" I asked, and she put a finger to her lips thoughtfully as she leaned down, resting her hands next to my hips and hovering provocatively over my quickly stiffening cock.

"I dunno- what would mom say if she saw this?" she asked, before leaning in and sucking my cock in its entirety into her mouth.

"She would probably have a heart attack," I muttered, restraining a groan, as my cock quickly stirred to full length in the warm, wet embrace of her mouth.

She shrugged, sucking on my length and flicking her tongue delightfully along the glans of my throbbing erection, and keeping my length completely submerged within her mouth for as long as she could manage, before letting me out with a little 'pop'.

She panted a bit, some slobber dripping from her lips obscenely as she dove back into the sloppiest blowjob I'd ever received in my life.

"You are insatiable," I noted, with pure admiration, as Abby licked the length of my shaft, coming to the soft place at the base before sucking one of my balls into her mouth and massaging it gently between her lips.

"You know, I've never been like this with anyone," she muttered, "maybe I'm just a whore for my little brother."

I groaned, the eroticism of seeing my older sister behaving so wantonly while taking dirty to me almost immediately pushing me over the edge.

She licked her way back up my length to the head of my cock, before looking up at me innocently as she took the mushroom head into her mouth and sucked on it as if it were a lollipop.

"You're melting my brain," I mumbled, and she smirked, before wrapping her lips around my cock again and trying to get my entire length down her throat.

She made it about three quarters of the way down before she gagged, taking me out and trying again, before coming up for air, her eyes a little watery and a mouthful of slobber pouring out all over my cock.

"Jeez, I don't know how they do it," she muttered, fighting back tears as her gag reflex seemed to get the better of her.

"Stop trying to compete with porn-stars," I chastised her, "besides, even when August deep throated me felt like nothing compared to the things you do to me."

She pouted, a little glumly, before unbuttoning the pajama top she wore, and stripping it off, while gesturing for me to get up.

"I want you to fuck my face, Caleb. Make me feel like I'm your whore," she begged, and I chuckled a little, surprised though aroused by this naughty side my sister was now showing.

I grasped her hair firmly, and aligning my cock with her mouth, I thrusted about halfway in a few times, before using a bit more force and roughly thrusting into her throat as far as I could go.

She gagged a few times, and I paused to see if she was alright, but she quickly shook her head and gestured for me to keep going, so with her hair firmly in my grasp, I angled her head up, and threw a leg over her shoulder, allowing me to thrust slightly downwards into her face, and my balls swung freely into her cheeks, landing with an obscene series of 'smacks' as I fucked her face with more enthusiasm.

Spit was now leaking in globs from her mouth, and the sight of her breasts, glistening wet and coated with a healthy sheen of saliva, jiggling as I thrusted into her mouth, was a sight to behold.

"Uh, I'm getting close," I muttered, and as she nodded, closing her eyes, I quickened the pace of my thrusting before withdrawing from her mouth and shooting my load onto her chest.

The first few spurts coated her chest nicely, and she quickly leaned in, trying to get some onto her face as I coated her body with spurt after spurt of my thick, creamy seed.

"I know I told you not to compete with porn stars, but that was right out of the top drawer as far as pornos go," I muttered with awe, and she smiled happily at the perverted compliment.

"Soo- am I better than the 'porn star of your dreams'?" she asked, putting her hands on her hips and winking suggestively, and my mouth fell open in shock.

That was a line from my love letter to August, and blood quickly rushed to my face as embarrassment immediately accompanied the recollection.

"Is that why you did this?" I asked incredulously, and she quickly shook her head.

"Maybe? I mean- no, not really."

She sighed, before continuing:

"You really do make me feel like being extra... kinky, okay? But I dunno... when I read your 'letter' I really started thinking you were in love with August, and I kinda checked out some of her vids..."

I flicked her on the forehead, and she pouted cutely in a way that sharply contrasted the slutty image that she cut, kneeling in front of me, topless and slathered in spit and cum.

"If you wanna be dirty for me, then I'm more than happy to oblige. But no more competing with August, okay?"

I kneeled down and leaned into her, planting my lips to hers, and our lips mashed passionately together several times before I broke away, placing my hand lovingly to cup her face.

"I love you, more than I could possibly love another soul," I muttered, and as I moved away from her, she smiled happily, scooping up a little cum from her chest with her finger and sucking happily it into her mouth in response.

"Shower and meet up for breakfast?" she asked, and I nodded, patting her on the head before heading off to get cleaned up.

***

After showering, I grabbed one of the leftover crepes from the kitchen then joined Abby in the living room.

She was sitting on the couch, her laptop open in front of her, reading something intently as she munched on a crepe of her own.

She was wearing her reading glasses, and I suddenly noted with surprise that they looked kind of sexy on her.

"Watcha got there?" I asked, leaning over the couch and giving her a quick peck on the cheek.

"Damn, if I knew you were going to be so much nicer to me, I would have started fucking you years ago."

I rolled my eyes and she smirked, before offering a bite of her crepe to me.

"Is that stuff for your project?" I asked.

"Sorta," she muttered, swallowing a bite and adjusting her glasses before continuing, "When I was preparing for your test, I did some research and came across this."

She indicated to her laptop screen, and I leaned over her shoulder to study it.

"Reddit?" I asked, and she nodded.

"Yeah, there was this thread that caught my eye. Wha- hey!" she complained, as I threw my body over the backrest of the couch, bouncing playfully next to her, and resting my head on her lap.

"Tell me more," I smiled up at her, and she shot me a scolding look despite smiling to herself.

"I didn't really take it too seriously when I first came across it, but it's been on my mind since last night, so I started reading again when I got up."

"Uh-huh. You've been a busy bee this morning," I noted, and she smiled mischievously.

"What? I was just doing good natured sisterly things," she announced proudly, and I smirked at her as she continued:

"I mean, if I wake up and my brother's all sticky and covered in fluids... it's my job as his big sister to clean him up, right? What difference does it make if I use a washcloth or my tongue? I'm still being a properly doting elder sibling."

"Your logic is sound," I muttered- "for a pervert," and she elbowed me in the ribs before continuing without batting an eye:

"Anyway, there was this subreddit opened by some guy called the toothbrush challenge."

"Toothbrush challenge?" I asked, and she nodded quickly.

"Yeah- it's based on some Japanese anime thing apparently; this brother challenges his little sister to let him brush her teeth for her, and its turns out to be a surprisingly erotic experience for the two of them or something like that. What can I say, anime is weird," she muttered, and I flicked her forehead.

"Anime is awesome," I corrected her, and she frowned before continuing:

"So some weirdo like you issued a challenge; brush your little sister's teeth and report back the results."

"Oh my god that's awesome. Please tell me someone actually did it!"

"Well most sound like made up stories, and even the realistic-ish ones might be fake, I mean they're just posts on an open forum, so it's up to you to believe them or not. But I came across this story-"

She rested the laptop on the coffee table in front of us, and I glanced at the page while she continued:

"The posts appear weekly for a few months, then every several months after."

"Hmm. That's seems like a lot of work to fake a story," I noted, and she nodded.

"Yeah. Either it's real, or someone just has waay too much time on their hands. But, whether it's true or not, it was still a hell of a read."

"Huh. So, what happened?"

"Short version? He brushes his sister's teeth and its awkward the first time; kind of like a silly thing that you just try once and forget about it? But then, they do it again, and they end up having a lot of fun. Fast forward a couple of weeks and they're brushing each other's teeth daily, and getting a hell of a lot closer along the way."

"Hm," I noted, my interest now piqued.

"Yep, eventually things start getting a little heated, and after a few intimate encounters, the two end up becoming full on lovers."

"Wow," I muttered, with fascination, "from brushing each other's teeth to lovers, huh."

"According to the poster, they were always closer than most siblings, and there was always something there between them, but it never really came out until they start the whole toothbrush thing."

I gulped, as I considered the story in the context of my own situation with Abby.

We were always pretty close.

A lot of people joked that we were more like a couple than siblings, but we never really took it on.

Had Abby's experiment given us the shove we needed to figure it out? And what did this mean for us going forward?

It certainly was food for thought.

"So- does it say what they're up to now?" I asked, and she blushed, suddenly a little shy.

"Well the last post was over a year ago, but according to it, they've been living as husband and wife for some time now, and they even had a son together."

"Wow. That's... something," I muttered, mulling over the information in my mind.

As of last night we'd become something like 'siblings with benefits', but was it really possible to be more than that?

Abby wasn't just my sister.

She was my best friend, and the person I looked up to more than anyone else.

I could say, without shame or doubt, that I loved her dearly.

Perhaps more so than I'd loved anyone else.

And unless I was mistaken... she felt the same about me, didn't she?

I considered for a moment talking about it, but the thought alone left me with a huge pit in my stomach, and the sudden inability to form sentences.

"Something wrong?" Abby asked, and I quickly shook my head, though as my eyes briefly fluttered towards her, I noted that the doubt and uncertainty I felt was mirrored in her gaze.

***

The week went by in a flash, and before I knew it I was packing up my travel bag and preparing to say a difficult goodbye as I got ready to make the long trek cross country to our little family home.

It was such a strange thing.

We were so comfortable with each other.

Being with Abby was easier than being with anyone else.

Period.

Yet the little matter of where we wanted this to go in the future seemed to remain just out of reach, as neither of us seemed capable of broaching the topic.

The week was pure, blissful paradise, and truthfully, I was afraid of bringing the matter up for fear that it would unceremoniously come to an end.

How do I say 'I want to be with you forever?'

And what would happen if she said no?

We were siblings, and all logic dictated that this relationship should never be.

As I stood on the cusp of the doorway, preparing to head out, Abby seemed as if she were about to speak, but the words never came out and eventually I left, a heavy feeling following me despite the loving kiss I planted on her lips, and the tender embrace we shared before I headed out.