Just Us Experimenting

Story Info
I become my genius sister's first, plus a threesome!
7k words
4.43
33.5k
45
Share this Story

Font Size

Default Font Size

Font Spacing

Default Font Spacing

Font Face

Default Font Face

Reading Theme

Default Theme (White)
You need to Log In or Sign Up to have your customization saved in your Literotica profile.
PUBLIC BETA

Note: You can change font size, font face, and turn on dark mode by clicking the "A" icon tab in the Story Info Box.

You can temporarily switch back to a Classic Literotica® experience during our ongoing public Beta testing. Please consider leaving feedback on issues you experience or suggest improvements.

Click here

Be aware of the small detail of the brother-sister fucking thing, virginity taking, a bit of brotherly reluctance, some cuckqueaning and, technically, an FFM threesome too.

Sooo... this is only for 18 and up readers who know this is all just fiction and should NOT be done in reality. Here's your legal warning.

And please, for God's sake don't take any 'medical science' in here seriously or as advice.

Got it? Thanks.

Oh, and I guess we're back in 2023, bitches.

- JCL & LM

= = = = = = = = = = = = = = =

Just Us Experimenting

by TeamLightningStar

= = = = = = = = = = = = = = =

Through confusing times, I become my genius sister's first. And a threesome ensues!

= = = = = = = = = = = =

Despite her many flaws, my sister is one amazing genius.

At 19, Dianne graduated college with a degree in chemistry. She was pretty much the top demanded free agent in our state for various pharma, tech and government companies, yet she chose a modest medtech one called Makrozoia because it wasn't shady, had a balance of female colleagues and they didn't hire her just to stare at her big, busty tits.

Me however, a respectable 5'11 man named Everett, had modest success as a copywriter and editor working from our home growing up because of my sensitivity to loud noises and bright lights.

In contrast, my sister is famous-slash-infamous around here in Columbus, Ohio and our circle of peers for being a foul mouthed, snarky, non-hygienic weirdo who just happens to be a female Nigel Braun.

Of course, I can confirm all of this because I've known her all my life. She's been mixing chemicals, making fires and calling them experiments ever since we were born in Thailand and grew up here in 'Murica. Now at our ages of 25 and her at 28, not much has changed. She has fussy black hair straight to her waist, only showers twice a week *at most*, likes baggy clothes, has armpit and leg hair and is still very anti-social.

All the hair stuff, I don't really mind. It's her stink that I do mind though and her fashion sense magnifies that. And she's not really mean per-se, just not very friendly and doesn't really go out of her way to talk to others she doesn't find many common interests with.

When she gets hot headed though, that's when the beast is unleashed. From a female Nigel Braun, she becomes a female Steve Jobs. I'd rather not go into detail so that I won't trigger my own war flashbacks, but she can blow up just as big as her old backyard experiments. Even since elementary, I'm the one who gets called over to talk her down or pinch some sense into her.

We weren't really as close these last few post-college years, but we still got along better than most sibs. These following months though as I write this, things have exponentially improved between us.

This started when I just broke up with a girl I've been with on and off again and I was sure this time we were clearly done. She was my first ever girlfriend, in fact, and since then, we've dated, stopped, became fuck buddies, dated again and broke up again in various cycles.

I've come to notice that Dianne becomes more nippy and argumentative whenever I'm dating someone, but, just like recently, when I'm single again, her flare ups stop and she becomes affectionate again like we were back then as kids.

However, I'm getting way too ahead of myself. It's said that to be a good storyteller, you need to 'show, don't tell.'

I don't really give a fuck about that too much, but I'll be going back anyway to when it all began in September.

= = = = = = = = = = = =

Glass doors beckoned me inside the white and gray walls surrounding.

An olive skinned beauty similar to my own skintone got up from the main desk, taking off her mask as she greeted me in the office outside their new lab. Her long hair swayed as she greeted me, "Hey, Everett. Nice haircut."

She was Evelyn. Dianne's recent co-worker, two years older, a bit taller than her, and the closest thing to a friend my sister currently has. Part Spanish and Russian, mixed just like us. She was the first person today to perk up my mood because of several things that happened that day.

I've known her for a few months now. She was just a couple of inches shorter than me and had that hot scientist vibe going in her lab coat and blue blouse-black pants combo suiting her figure and perfect chest. Of course, her attire had to match their place of work.

Speaking of the place, it was like a sci-fi set next to us. On the other side were beakers, white tables and little tubes with all sorts of containers and powders of different colors surrounded by see-through fridges and tray cabinets and dozens of whiteboards with equations that were essentially a different language to me. Separating us from the lab were another set of automated sliding glass doors accessible only by fingerprint and passcode. All of this added to the gray mood I've been having, which thankfully Evie didn't pay mind to.

I greeted the kind lady, "Thanks, Evie. You got good curls in your hair. Looks great on you."

"Aww, thanks Ev. Where'd you get your cut?"

"I found a new barber near our neighborhood who does undercut fades well. So, what's the damage today?"

We already had a mutual understanding of 'who' does the 'damage' whenever I fetch my sister. Hint: Her name rhymes with 'My hand.'

"It's tame this time," she replied. "She just told off an inspector talking about her body odor."

"Hmm... You all wear hairnets and disposable scrubs anyway, right?"

"Yeah, but you know how Di gets."

"What, did she insult him by saying he's some kind of smell obsessed pervert?"

She smirked, "Pretty close. She told him he'll never get a date if all he thinks about is how a woman smells. Then she went off on how none of her body odor is getting on to the mixes anyway so why the eff did he care. Except she didn't say 'eff.'"

That sounds like Dianne alright. "Did it go on longer?"

"No, it stopped there. He just moved away and went. I already warned him before he even approached her. His own roasting, I guess."

The lab doors open and, speaking of the devil, Dianne steps out.

"Heya, sis."

"Was that text true? You broke up with that Renee cunt? That's great!"

Yep, her reputation precedes her. This 5'7, rosy cheeked, snow white skinned woman with rounded rectangle glass, plump waist, thick thighs and a 36F bust size truly was a sailor mouth. Don't ask why I know her bra size.

"...Nice to see you too, Dianne."

"You didn't answer my question," she noted.

"Can you stop right now? I'll tell you when we drive."

"Fine. You better not be lying. I'm going, Evie. Thanks." She waved to her friend and logged out by putting her fingerprint on the biometric. The little machine on the front desk lit up and showed her name and out time: 'Dianne Crawford Linasmita' and 'September 9, 8:19:21 PM'

"Thanks, Evie," I also waved.

"Bye Ev. Bye Di."

When we got to our car and drove out of her office building, she asked me at a stop, "Sooo... What happened to Cunt No. 1?"

She numbered all of my exes by chronological order of when I met them.

I had to raise my voice, "God dammit, Dianne. You just can't stop pushing people's buttons don't you? Yes, we broke up!" Then I remembered to breathe deep and continued calmly, "All we had left in common was sex and nothing else so we're done. Happy now, you misanthrope?"

She went silent until the lights went green. "...Okay. I'm sorry," Di said, sheepishly.

"Good."

I guess I'm lucky enough to be the only guy in the world who can push back on her BS. She didn't stay quiet long, however. She never does.

"I just think that this is a good decision, okay lil' bro?" She said in undisguised joy, patting my shoulders and cheek from her passenger side.

"I see you're still not over your brother complex for me."

"Hah! Nice joke, buddy."

I just huffed and let it go.

= = = = = = = = = = = =

I think it's around 2 in the morning now. Dianne's finally asleep. I'm still here next to her in her queen bed. Finally at rest. I had to babysit her here when she drank again.

It's sad that she's only at her prettiest when she's sleeping, but at least she can still make a change. I found myself drifting to sleep until I was woken up. Light was shining from her window. Must be sunrise.

To my left was Dianne moving herself to sleep on my shoulder. She moved my arm to cover her as she rested. "Sorry, Ev. Go back to sleep." She had an old shirt on with the sleeves cut off and some pink boxers.

"You don't have work this Saturday, right?"

"Yes, no work today." She clung to me like a koala on her branch. I tickled her armpit, some hairs even jotting out. "Mmhh, don't be a dick."

"It's cute though. Your little hairs."

"Is that serious or a rib?"

"I'm dead serious. If only you'd shower a bit more and were less standoffish, you'd be golden."

"We can't always get what we want."

"True... But we can try."

= = = = = = = = = = = =

To my left was the sun shining brighter this time. Lunch time, I'm guessing? Also to my left, Dianne's position changed into being the little spoon as my arm again covered her. Likely moved by her. This girl really does have a brother complex.

"Ev, you awake?"

"Hmm? Yeah."

She turned to face me. "Thank you." Then she held my cheeks and gave me a chaste peck on the lips. After a whole decade of no lip contact, she was kissing me again.

I thought we were over this, but it was fruitless to deny her. She needed the comfort anyway.

"You taste like milk," she said.

"Oh, I drank some from your fridge last night. Hope you didn't mind."

"It's okay," she said before pecking me again.

"Dianne..."

"What? Don't make it weird. Unless..."

She had the audacity to look at my boxers and catch me at half-mast.

She smirked, "And you say I have the complex."

"That's just morning wood!"

"Yeah, sure," and her body shifted again, moving on top of me and kissing me again. Then, her kisses turned into a deep smooch while her tongue touched mine.

I pushed her off, "Dianne! What the hell! We've been through this before."

Yes, this has happened multiple times in the past. I don't wanna talk about it.

"Hey, you said last night you'll give me what I need. This is what I need. Are you going back on your word?"

I knew I shouldn't have said that last night when she was being sad and touchy feely in her drinking again.

"You're such a bratty little imp sometimes, you know."

"I do know, but are you helping me or not?"

"...Fine. Just don't expect me to kiss you back or whatever."

"Whatever you say, Ev. You like this too."

"Keep telling yourself that."

Her tongue went back to mine and her lips started sucking. I liked her warmth, at least, so I held her close to my chest.

She broke off, "Isn't it sad. You're still the only person I've ever kissed?"

"If you don't like it, by all means we can freely stop."

Sleepily, she said, "Nooo... I like your kisses. You should take it as a compliment that I don't need other guys' lips."

"I feel more like a default option instead of a choice."

"Nah, don't think like that, you Eeyore. You're like a favorite food I don't need to grow out of. Now I can have you every day again."

"...That sounds like innuendo."

"Hah, you wish."

She gave a love tap to my head with her knuckle.

"Ow!"

"That's never happening between us, dude. You're starting to sound more like a sibling lover than I do."

"Remind me who's kissing who now?"

She proved my point by kissing me again, "This is a mutual thing. Don't fucking lie, you pussy."

"There's no winning with you. Just don't french me again, please."

"Fine, you prude."

And this went on for about a few more minutes.

At least things calmed down after that and with the days after. The coming weeks were a LOT better.

And I got to know Evie better through our trio dinners. That's a plus. Even got her number. You know, to keep track of how Di is feeling at work. Aaand maybe some one-on-one night outs here and there that Di doesn't know of.

Unfortunately, things got out of hand again, this time not because of Dianne's faults.

= = = = = = = = = = = =

It was a Sunday afternoon at the end of November when I was informed that my sister was physically attacked in a grocery store by some unknown woman. She was given a check up and was now talking to police.

Me and Evelyn got out of my house and went straight to the police station.

I found Dianne sitting in a plastic chair next to a desk, leaning down and holding her stomach in pain.

"Di, what happened?"

She looked up, saw me and Evie and hugged me, "Everett! Oh god, a bitch crazier than me punched me in my stomach!"

"What? Why?" Evie asked.

"I took the last five packs of Cheezy Poofs and then this random crazy woman got mad that I got them first! I said I would have given it to her if she weren't so rude, then she tried taking one out of my cart. I tried to stop her, but she wouldn't let go of the pack. So I let her go, then she slipped because of her pulling at it so hard.

It all happened so fast! She got up so quick, then she lunged at me. So, I put her in a headlock on my armpits. She was screaming how bad I smelled, and then she started punching my stomach! I let go, and then some workers chased her off, I guess."

"Jesus. What'd she look like?"

"She was tanned and had black hair and a hoodie. It happened so fast, I don't even remember much what she looked like. Ev, I really want to go home now."

Evie asked, "What about your stomach?"

"I don't wanna talk about it here."

We took her home and ordered pizza for dinner. 'Hawaiian' with ham and pineapples. Dianne's fave. I never really thought the name 'Hawaiian' fit the toppings, but I'm getting off topic.

We just finished dinner and sat together in Dianne's kitchen.

"Feeling better now, Di?" I asked my sister

"I need a long dick in me," she replied like it wasn't the biggest non-sequitur of all time.

Evie spoke, "Uhh... Dianne? Are you okay?"

"I mean it has to be an actual dick, it can't be a silicone one. I'm allergic to silicone or latex. That's why I wear fabric gloves under my lab gloves."

I said, "Are you going to tell us the reason why you want dicks?"

"The doctor said I was punched near my cervix area. The pain I've been feeling is coming from there. It would need careful massaging, like if someone was injured in their tailbone they'd have to finger you up in the butt and get there to fix it. Since he didn't have anything to put up there and I didn't want him to, he said I'd have to find a partner with a big enough dick to hit my cervix and massage it there with his cockhead."

"Dianne... What the fuck are you talking about?"

"It's true! Look, I have the doctor's note here."

And she showed me. It literally said there on the doctor's note with the clinic's masthead: 'Patient must find a sufficiently engorged sexual partner to massage her cervix from within the vaginal area. Let the partner gently hit the lower or upper parts of the circular cervix area when laying flat, not the center. Massage above pelvic groin area for best results. Do it for five minutes as needed.'

"The fuck happened to medical science?"

Scratching her neck, Evie asked, "Well then, are you going to look for a partner online now?"

"I was hoping you could lend me my brother's dick, 'cause you're seven inches, right, Everett?"

What the actual FUCK!?

Evelyn played it safe, "Dianne, what are you talking about now?"

"You two are banging, correct? So can you just skip the denial?"

I huffed and had to answer, "Dianne... Yes, me and Evelyn are intimate and dating, okay? How did you guess?"

"Enough of that right now! I need your dick inside me, please! Evelyn, is that fine with you?"

"Uhh... I... I don't know what to say."

"Dianne, don't we have other options?"

"No, Everett! The doc gave me pain pills and other pains to halt some of the pain and bleeding, but it's only good for 12 hours each. I could only buy enough for 10 days. Even then, the pain can vary from fine to unbearable. Do you think I can find a guy online who isn't a dick, would find my lifestyle attractive and has a big enough dick that I would trust enough not to cum inside me? You ARE seven inches, right?"

"How did you ev-"

"Evie told me, but she didn't mention your name. I figured it was you when I noticed both of you would suddenly be busy after dinner, and you said you were meeting up with friends late at night and on weekends!That wasn't the only clue either. You two weren't exactly sneaky. Please, just help me already? It takes long for you to cum, right?"

Evelyn stood flabbergasted. I guessed it was more of Evie sharing our sex life without naming me. I tried to reason with her, "Dianne, we-"

"Are you gonna FUCKING help me or NOT? Tell me NOW, you shithead! I'm still in PAIN!" And I should have known there was no reasoning with her.

"Dianne... Fuck! Fine! You owe me for this! We're gonna need a condom!"

"NO CONDOMS! I fucking told you I'm allergic to latex and silicone!"

"Gaahhh! Whatever!"

"Finally!" She went over to Evie and shook her from her frozen state, "Evelyn, I'm sorry about this. I promise this is only for my pain. I'm not going to steal him away from you. In fact, his reaction right now is proof that he's doing this just to help me. I'll understand if you hate me, but please... I hope you don't."

I looked at Evie carefully. I was scared that she might storm out or hit me or anything negative.

...But she floored me with her response.

"Can I watch?"

"WHAT?" Both Dianne and I said out loud. My sister even pulled back from her as if she touched hot iron.

She went further, "I mean... That's my condition. I'll only let you borrow him if you let me watch both of you fuck."

Both of these women have completely gone nuts!

I pleaded with her, holding her arms, "Dear God, Evie! Baby, please, no. I know we've been talking about you wanting to experiment with your cuckquean kink but-"

"Everett, this is the best opportunity for that! A girl we both know that won't steal you away and that we both trust! You're both gonna fuck anyway, so just let me, okay, baby?"

Dianne had to ask though, "I might regret asking, but what's a 'cuckquean'?"

Evie answered for us, "Means I wanna see him fuck a girl in front of me. Simple as that. But I get a say on what you both do."

Of course, that just suited Dianne well, "Okay, then. What are we waiting for? I can feel my cervix is about to scream again and so will I if you don't put your dick in me, Everett!"

What the hell did I get myself into?

= = = = = = = = = = = =

I heard a knock at the door.

"She's ready, hon." It's Evie.

I opened the bathroom door from inside and stepped out. Evie was wearing her white coat for some reason.

"Oohhh... Those are my favorite shorts of yours," she said, noting my loose dark greens. Evie rubbed her hands on my stomach hairs. "She's gonna love all of this like I did."

"Can I ask why you're wearing your lab coat? And why do I feel like I'm being pimped out."

"That *is* what I'm doing. Roll with it, babe. Tonight, we're experimenting. Get it?" she said with a kiss on my cheek.

She took my hand and led me to Dianne's bedroom.

My sister was there waiting, freshly showered, covered in her sheets and sitting on the bed. Already naked underneath.

"Oh, sweet Di, I have a surprise for you!" Evie practically sung to her, "But first, you need to unwrap *your* surprise too!"

She pointed at the covers.

"Let's get this over with."

As she said, my sister opened her arms and showed the beauty of her snow white, busty body. Her tits were huge globes, a cup or two bigger than Evie. Pink nipples poking out of cute perfect pink rings. She had the right amount of plump on her tummy and it suited her figure. Her curvy hips led to her hairy pussy and loose brown-pink lips. No points for guessing she was 'au naturel' down there too. And her thighs and feet look amazing as well.

12