Prodigious young scientist Dr. Sasha Kinley went to activate the mass accelerator. My heart was in my mouth. Years of research, thousands upon thousands of dollars of funding, all riding on this one experiment. We wouldn’t have the budget to run it again; everything had to be perfect.

A slab of meat sat under a long metal rod, and we were going to see if, put simply, we could make more of it. Mass from mass.

I could barely watch as Kinley flicked the switch, and the machine started to hum and vibrate, powering itself up. If everything went to plan, the meat would be hit by a charge of particles, which would stimulate the tissue inside to duplicate itself. All the calculations were correct.

From behind my screen, I saw Sasha stride back, moving for the safety of my position, when something went wrong. The machine continued to charge, way beyond its power needs, and began to overheat. Sasha turned, noticing the ominous signs, and sprinted not towards the safety of the screen, but back to the machine.

“Sasha, no!” I called. It was too dangerous. I leapt from behind the screen, as a massive wave of energy burst forth, sweeping the entire chamber.

And then, nothing.

Steam and smoke filtered through the room, and dangling wires and bits of machinery sparked. The device looked just about held together, but it wasn’t going to work again with serious repairs.

Sasha and I picked ourselves up from the floor, brushed down our lab coats and – remembering – ran to the central plinth where the slab of meat was.

She grabbed my hand, as I lifted the glass container, a slew of smoke rising out. We both watched, as the smoke cleared…and the same blob of meat sat there.

Crushing disappointment filled me. All this work. Years of both of our lives, all for this. All for nothing.

“I’m sorry, Sasha. I really am.” I pulled her close.

“I know, Phil. Me too-wait. Wait.”

“What?” I looked up, following Sasha’s finger, which was pointing towards the meat, which was bubbling and vibrating, before…growing. It was replicating itself, and the blob of flesh was…getting bigger. Slowly self-duplicating. It was an incredible sight to see.

“We…we did it. We did it!!” We both shouted, jumping and hugging each other. The sleeves of my labcoat felt a little short as we high-fived, and in fact all my clothes felt a little tight. This was nothing compared to how Sasha looked. She suddenly seemed very concerned indeed.

It suddenly occurred to me that Sasha received a full-on blast of this thing – if it worked, she’d been hit too…was she going to start duplicating?

In answer to my question, Sasha’s shirt began to tighten, and she did her labcoat up hastily, covering up and signs of growth.

“Nothing to see here”, she laughed. “Nope, nothin’ going on.”

“Sasha.” I frowned, pulling the sleeves of my labcoat down, “This is vital medical research. Are you changing?”

“I’m not the only one”, replied Sasha, pointing square at me. Oh god. I was hit too. I looked at my arms, which were now way out of the end of my labcoat sleeves, which was beginning to look a little like a kids’ jacket on me. Was I…growing?

All the while, Sasha’s growth appeared to be confined mainly to her chest, which was bulging outwards at quite a rate. As much as she tried to cover the expansion with her labcoat, I could see two bumps pressing forwards underneath, unable to be fully disguised. I couldn’t help but find the whole thing equal parts exciting, terrifying and arousing. It had worked! But we’d been affected. But boobs!

The more she tried to pull the labcoat tight over her swelling bust, the bigger they looked, as they bulged and swelled over her shrinking clothes, no longer able to do the job they were made for.

“Hey, I’m growing too. Let me see the damage.”

She relented, and removed her labcoat, to unveil two large mounds on her chest, a tiny black bra just visible underneath her work shirt, though it looked like the bra was going to snap off at any moment.

“Oh Phil, they feel so large and heavy. What’s going to happen?”

“I have no idea, Sasha. I have no idea.” I grew a little taller while I spoke, inching up and up, stretching slightly out of my pants, and growing more and more into my labcoat. Everything was quite a tight fit now, but I’d been hit by a lot less of the ray than Sasha; the real tightness was going on over there.

Sasha’s shirt grew more and more stricken as her breasts expanded into it. The buttons were just about holding for now, but two five inch bumps squeezed into the tight cotton, pushing aside the buttons to reveal big round gaps where the shirt was being pulled aside by the width of her growing knockers. Underneath, large pink masses of tit flesh were visible, and the squeezed more and more through the holes as they swelled bigger and bigger.

At the same time Sasha, like me, started to grow.

She wasn’t a tall girl – only about 5’3 – but that wasn’t going to last for long. My growth had only been a couple of inches – from around 5’8 to 5’10 – but she was hit by a full dose. Already her legs and torso were starting to stretch, bulging and thickening as she panicked and looked around the chamber for something else to wear. It was a spartan, clean environment though; she didn’t have any luck.

Her loose black work pants gave her a little leeway as her legs and particularly her ass started to expand. Where once she sported a very modest pair of cheeks, her butt now began to fill out, swelling bigger and bigger with every second I looked at it, bulging and growing bigger and bigger, packing out her tight trousers, which were lifting up at her ankles, pulling further and further up her growing legs, which thickening gorgeously around the thighs.

Dr. Sasha Kinley was blowing up in all the right places.

“Phil, are you feeling much more…no, never mind.” Asked Sasha, as her breasts pushed harder against her straining shirt, filling up more and more of the diminishing space beneath it, bulging above and beneath the tightest area in the middle. Hard hard nipples poked through the fabric.

“More what?” I asked, my growth seeming to be slowing as I approached 6ft. I hoped she was going to say horny, because this whole experience was driving me a little bit crazy. I was just about still fitting in my outfit, but it reminded me of when I had a growth spurt when I was thirteen, and my parents couldn’t afford to buy me new clothes for a few months.

But childhood memories aside, I was majorly turned on.

Sasha had more swelling of her own to attend to, as her pants began to tear around the waist. Her butt had gotten huge, and was filling the fabric at the top of pants ‘til it was fit to burst, which it probably would soon. Her tits were still swelling and bulging, and she was growing taller and bigger-assed as I watched her. She also looked like she was trying really hard not to be turned on.

She wobbled up to be almost 6ft herself now, and breathed deeply, her massive chest heaving. I could see hints of her huge tits beneath the shirt, squeezing through the gaps in her buttons, bulging forth, trying to escape. She stepped very close to me, and lowered her chin, looking at me square in the eyes.

“Phil, I don’t know what’s happening to me, but it’s…how do I put this? Exciting. Very exciting.”

“I know! We’ve achieved our life’s work! And we’re both so young! Mid 20s, and we’ve done what we were put on this earth to do. And it works on humans! You bet I’m excited too!”

“No, I mean…um, oh fuck it.”

Sasha grabbed the lapels of my labcoat, and kissed me passionately on the mouth. I could feel her monster tits press into my chest, and I loved their swollen, firm sensation, warmly pressing forwards as we played fiery tonsil-hockey.

When we eventually pulled away for air, Sasha was a couple of inches taller than me, and still growing. Her pants were skin tight on her legs now, and looked like they weren’t going to last much longer. She smiled, embarrassed as she continued to grow taller, her long arms and legs packing her shirt and pants, before a button pinged off her top, right in the middle. Her tits were getting too huge to contain.

“They look like they’re about eight inches out in front of me now.” She mused, ever the scientist. “I’ve gained so much mass! This machine is incredible.”

“You’re incredible.” I replied. “And you look amazing.”

Sasha blushed, as another button pinged off her shirt, her bulging breasts busting through. I could almost see them now, and they looked huge.

“You don’t think I’m too…big?” She arched her back, sending a third button flying off, as a fat mound of cleavage spread through the center of her shirt. Her huge tits were nearly on display now – she was doing this on purpose.

“Before you get too big for me, would you like to…I mean…?”

“I would say tear these pants off me, but I think I’ve got that covered.” Laughed Sasha, as her large, long thick legs formed tears down either side of the pants, the pleats beginning to rip as her huge ass thickened and bulged. It looked so good.

I strode up to Sasha, pulled her tight to me, and kissed her hard on the mouth. I had to lean up a little to get there – she was 6’4 now – but it was worth it. Her huge tits wobbled into my chest, and I grabbed her ass, which was truly gargantuan, bulging and bursting against her tight pants. So tight and firm; I couldn’t believe something so big could be so pert. Her tits looked the same, riding high on her chest, despite approaching the size of firm, lusciously ripe watermelons.

Sasha slowly walked me backwards, giving me a perfect view of her massive, bouncing titties as they swayed and bulged through her shirt. A couple more buttons pinged off as we walked, and the true scale of her enormous, tear-shaped boobs became apparent. If I had to estimate, I’d’ve called these an M-cup, but it was so hard to tell. They were so huge, and her shape was changing all the time; cup measurement were futile. They were colossal, round and firm, and I wanted to bury my face in them.

As if to grant my wish, Sasha burst out of her shirt just at that point, and her massive tits hung free. Their sheer scale took my breath away, as did their perkiness and large nipples. It was an incredible sight.

“You like?” She enquired, lifting a huge, water balloon-like boob in one hand, as it grew bigger, spilling slightly over the edge of the hand that held it. With her other hand, she pushed me into a wheeled office chair. My growth had practically stopped, but my extra weight still surprised me.

I nodded, dry mouthed. This was too perfect.

Sasha leant down from her new height (about 6’7), her long, toned legs rippling, bulging out of those tiny-looking pants, and swung one of her massive udders down towards my mouth.

“Suck on it while I grow.” She ordered, her legs and butt finally ripping clear of her black work pants. A pendulous nipple attached to a huge breast slowly lowered into my mouth, and I began to lick and suck on it as I pulled myself out of my own, far-too-small clothes.

I pulled Sasha’s massive form close to me as I kissed and sucked her tits, and thrust my huge member against her leg, showing how hard I was.

“Ohh, you’ve been doing some growing of your own, haven’t you?” She purred.

I looked down, and my dick definitely seemed bigger than usual. I wasn’t hit fully by the experiment, so the effects weren’t going to be as extreme as Sasha’s, but it certainly looked an inch or two bigger. A perfect fit for Sasha’s new, enlarged body.

“I’m so fucking wet.” She moaned, tearing off the remnants of her clothes, and letting her blonde hair down from its tight bun. She stood over me with her massive thighs, her light-eclipsing jugs creating shadows over me, and lowered herself onto my rock hard dick.

“Ohhhhh that feels amazing!” She groaned, taking me fully inside her, her massive fat tits bulging into my face. I could feel her huge ass bouncing on my thighs, and loved how big and thick it was. Her feet touched the floor no trouble, and her legs would only be getting bigger and longer, giving her complete control over the pace and energy of the sex. She chose quick and high, if you’re wondering.

Soon Sasha was riding my newly-massive cock like a pro, her preposterous, still-growing tits bouncing madly and inflating in front of my very eyes. I loved seeing them bulge bigger this close to me, creeping across from her massive, still-growing form towards me. The taller she got, the easier it was to direct her huge nips straight into my mouth, where I licked and sucked them as she rode my cock like a pro.

I’d never seen this side of Sasha before – we’d worked together for years – but I was sorry it had taken this long. She was an absolute demon, fucking me like a girl possessed.

“Oh Phil, I’ve wanted to do this for so long! Ohhh!” Every oscillation of her gorgeously tight cunt sent shockwaves through her body, and brought the both of us closer to coming. Between my enhanced cock, and her very enhanced body, this was clearly something of a fantasy for both of us, and one we were both enjoying more than words could say.

Sasha’s tits grew bigger and bigger, spreading forward into my mouth and I ran my tongue all over their fleshy goodness. They were so pert and firm, so stuffed with sweatermeat I just wanted to bury my head in them. So I did, licking and kissing the massive mounds of flesh as we both came closer and closer to climax.

And then I knew it was coming. As Sasha’s medicine balls began to reach me without her even leaning in, and as her height grew to nearly 7ft, this giant goddess riding my engorged cock, and as I felt her massive booty swell into my thighs and I pictured her standing up, trying to fit into her old clothes, busting out all over the place, I felt myself starting to come.

It was a slow process, building up and up, but my cock started to swell with semen, and then pump, again and again, firing big, thick, creamy blasts into Sasha’s beautiful waiting cunt. More and more – the device had certainly multiplied this – the orgasms came thick and fast, and sent Sasha into overdrive.

She was practically screaming with joy, grabbing her hair with both hands as she rode my cock, experiencing massive, shuddering orgasms of her own that pulsated through her massive body, reverberating back down into my cock and fuelling mine.

This went on for quite some time, until finally, it was over.

I lay back in the office chair, panting, as Sasha peeled her enormous, over 7ft body off me, and sat on the floor, a small river of cum oozing out of her cunt.

For a time, there was nothing but the sound of heavy breathing and a deep, satisfied silence.

And then:

“Oh my god, we are gonna make so much fucking money!”

I felt myself growing hard once more. Yes we were.

—

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