11/16/20XX

I found myself in what seemed to be a normal gym. Except it was completely empty aside from myself, Jenna and Max. I was my old height of 5’8” but as the girls passed from behind me I noticed they were still taller than I was. I estimated them to be about 6 feet tall. Their bodys were lean and toned, not quite musculare but you could still tell they worked out. They were each wearing a combination training bra and spandex shorts, dark black for Max and a cute pink for Jenna. Underneath their shorts a defined bulge lingered, tame for now. 

Each girl stood to either side of me with their arms crossed. Their shoulders pressed into mine and despite being a totally normal height I felt small between them. 

“Ready to get started?” Max spoke.

“Oh yeah, more than ready~” Jenna giggled. She winked down at me and then followed Max over to the center of the Gym. 

Max started with bicep curls first. As I approached her she gave me a wide smile. She was curling a beefy looking 25 pound dumbbell. With every repetition her arm grew larger and more defined. I placed my hand on her taught bicep and felt it flex under my fingers. 

“Give it a squeeze,” She whispered. “Go on, I can take it.” I hesitated for a moment and then compressed my fingers on her arm. Nothing, it may as well have been coiled steel. I readjusted, getting a better grip. Once more I squeezed. Max giggled as my knuckles went white and my face burned red. Eventually I gave up with a gasp. Max dropped the dumbbell and stood. It made a loud *THUD* on the floor, startling me. Looking down I saw that it wasn’t 25 pounds like I thought but actually 100.

“W-wait wasn’t that a 25 pound weight?” I asked, confused. Max raised an eyebrow.

“Babe, why would I start my warmup with something as light as 25 pounds?” I looked up in awe, only to find myself face to face with Max’s struggling bra. She had grown to nearly 7 feet tall. As I looked over her body I was met with large defined muscles, easily larger than those of a casual weightlifter. Her abs glistened with sweat and her firm pectorals caused her D cup breasts to jut out from her chest. “Why don’t you go talk with Jenna for a bit, I need to set up the equipment.” Max said, more like an order than a suggestion. She spun me by my shoulders and gave me a gentle shove and a slap on my butt. I stumbled forward towards Jenna, who was running on the treadmill. 

“Hey Trev! Come to watch me beat my record?” Jenna sang down to me. Standing just beside her I could see the readout on the treadmill’s screen. It read 10mph. Certainly fast, but nothing exceptional. Jenna increased her pace and I watched the number slowly creep upwards. 11mph, 12, 14, 16, 20. She was really going now and I looked down at her legs to see them swelling with thick, hard muscle. They were more than twice as wide as my own legs and still growing. 24mph, 28, Jenna paused her acceleration to look down at me and wink.

“That’s the world record for fastest human, and now….” She exerted slightly more effort, 32mph. “That’s the new record but I’m not done yet!” She turned back around to focus. I was transfixed, switching between her burgeoning legs and the impossible treadmill readout. 36mph, 40, 45, 50, 60, 70, her acceleration was increasing and the whine of the treadmill was reaching an impossible pitch. 80mph, 100, 120, 140. Her legs were a blur. I wagered that if I were to try and tough them they’d shear my arm clean off. 180mph, 220, 260, 300, 350. She was now running fast enough that even the fastest supercars would be eating her dust. 400mph, 500, 600. She could now outrun a commercial airliner. 700mph, 800, were she actually moving she’d have broken the sound barrier. 900mph, 1000, 1200, 1500. She could now outrun bullets. 

Slowly Jenna began to back off her superhuman speed. When she finally came to a stop and stepped off the treadmill to stand in front of me I staggered at what she’d become. She stood 9 feet tall and like Max her whole body had become more toned and muscular. I was eye level with her glistening abs but they were far from her most impressive feature. Her hips widened into a titanic pair of thighs, each one 3 times wider than my whole body. Her taught, toned calves were the size of watermelons and her ass was a perfect peach shaped dome of pure strength. She threw a towel over her shoulder and sighed happily. 

“All this working out is making me horny!” She stated. I looked and sure enough her shorts were barely restraining the growing bulge of her cock. It looked to be over a foot long and still growing while her testicls swelled impatiantly. I looked up at her nervously only to see she wasn’t looking at me but at something across the room. I turned to see Max at the bench press about to start her lift. 

I made my way over just as Max was lowering her second repetition. She let out a frustrated grunt and turned to me.

“Hey could you increase the resistance on this thing? I’m not getting a pump outta this setting.” I turned to the machine's console. Like the one she had at home there was a multiplier setting to increase the effective weight on the bench. Unlike our home gym this one also had a handy readout to indicate what the current setting was. It currently read, 2,000Lbs. I gulped, and turned the knob, increasing the weight to 4,000Lbs. 

“Thanks!” Max said as she lifted again. She completed two reps and then stopped again. “Actually just keep turning it, this is already too light.” I turned it up to 6,000Lbs and Max began lifting again. Everytime she completed a lift I increased the weight. 8,000Lbs, 10,000, the display switched to showing tons instead. 5 tons, 6, 7, 8.

“Speed it up babe! I’m finally getting something.” Max said gleefully. I watched on as her arms swelled from watermelons to beach balls and beyond. 10 tons, 12, 14, 16, 20. Despite lifting more than 10 times the weight of the average car Max still seemed unchallenged. I subconsciously increased my pace. 40 tons, 80, she was now lifting more than the weight of a main battle tank. 120 tons, 180, 240, 300. She was now lifting 3 times the weight of a blue whale. 400 tons, 500, 600, 800, 1000, 1,500. She was now lifting the equivalent of a small destroyer. 2,000 tons, 4,000, 8,000, 10,000. She could now bench press the Eiffel Tower. 20,000 tons, 40,000, 80,000, 100,000. After reaching the weight of a U.S. Navy Supercarrier and still looking as though she was putting in next to no effort Max rested the bar on its supports and sat up. 

“Well that was disappointing, I couldn’t even get a good burn with all that.” She then stood before me. Somehow during the whole ordeal I had missed her incredible growth. As she stood she rose, higher and higher, until I was starting at her kneecaps. She must have been at least 20 feet tall. Her top and shorts had long since torn away and her mountainous breasts hung freely. Also now free, her nearly 15 foot cock arked over my head thicker and harder than an oak tree as her testicles swung like church bells far above me.. 

I felt a pair of hands on my shoulders. Jenna was behind me, looking up at Max. 

“Want to help me catch up with her?” She whispered into my ear. I nodded without turning around. Max looked on, amused as Jenna walked me over to a yoga mat. She took her position and began streachting. 

“H-how can I help?” I stuttered. Jenna looked at me and seductively licked her lips.

“You can watch.” 

She started on all fours, alternating between leaning forward and back with her ass in the air. With every stretch her body lengthed. As she worked through her poses I could see that her cock had inched its way out of her shorts and was working its way down her leg. First to her knees and to then her shins. Before it could make it any further her shorts snapped off her waist and her dick flug free. It pulsed and jiggled as it, and she, grew. Finally, she ended with the Lord of the Dance pose, one foot raised and held in her hand with the other hand reaching before her. Her cock extended from her waist like a third arm, adding a surreal effect to position. She was now the same size as Max at 20 feet tall. The tip of her cock was leaking gallons of precum on the floor in front of me and I looked to see Max slowly stroking herself at the sight. 

Once Jenna was done she took a few steps to cross the gym to where Max was standing. They embraced each other like lovers, their mouths locked in a passionate kiss. Their breasts squished together and spilled out the sides of their entangled bodies. I didn’t want to be left out but I was having trouble navigating the nearly 2 foot deep sea of precum that had coated the entire gym floor. Eventually I gave up and climbed on top of a table to free myself. 

Max had lifted Jenna up and was guiding her cock into her waiting pussy. At the same time she had taken Jenna’s cock into her mouth. Then the two of them began thrusting into each other. Max’s footsteps shook the foundations of the building as she brought Jenna over to where I was sitting. She lay Jenna down and continued thrusting into her on her knees.  Jenna’s cock, popped from Max’s mouth but not wanting to leave her partner unsatisfied Max grabbed me with one massive hand and placed me on Jenna’s chest, in front of her throbbing dick. I went to work kissing and sucking its tip, though it was far too large to fit into my mouth. 

Max came first. With a tremendous roar of ecstasy she ejacualted thousands of gallons of cum into Jenna’s womb. Jenna’s whole body twiched as she filled like a water balloon, almost knocking me off balance. An instant later she followed suit, sending a torrent of semen over my head as he bucked her hips in pleasure. The three of us lay there, panting in post coitial bliss. I was only able to stay out of the 6 foot pool of cum that covered the gym floor by resting on Jenna’s massive bust. It was warm and growing warmer.  

I woke to the sound of stretching fabric and moaning. Last night I’d fallen asleep in between Max and Jenna on the oversized couch in the basement. Both girls were seated next to each other and I was sprawled across their juicy thighs. The stretching and moaning, I thought was coming just from Max but I soon realized it was coming from Jenna as well. Their hot skin expanded under my back and I watched as they both grew to encompass more and more of my vision. Jenna was definitely growing faster than Max but Max had a tremendous lead. I felt something pressing into the back of my head, which was on Jenna crotch. I didn’t need to look to know what it was. Her cock was turned away from me to make room for my head but her balls were swelling right where my head was laying. 

I may have been safe from Jenna’s dick but Max’s had a mind of its own. It was resting on my chest like an oversized blanket. I realized this was the first time in while I’d seed it soft. Even so it was still larger than my whole body and rapidly growing. I noticed a little too late that an ever increasing amount of precum was spurting from its head. I quickly scrambled up Jenna’s chest and rested on the high ground of her shoulders as her lap filled with Max’s pre. I’d still gotten a little bit on me, so I supposed I’d be saying goodbye to 3 feet tall soon, though hopefully not by too much.  

The whole ordeal lasted maybe fifteen seconds, after which the girl’s bodies rapidly cooled and they began to wake. Max stretched her arms over her head and Jenna stood, dumping the several gallons of precum off her lap and onto the floor. She didn’t even seem to notice. She did notice that I was riding on her shoulders. 

“Hey lil’ bro. How’s the view?” She teased. I laughed nervously.

“Pretty good, I guess this means you’ve finally cracked 8 feet huh?” Jenna pondered for a moment.

“Should be 8 foot 2 I believe. And this,” she took her cock in both hands. “This should be 28 inches if I’m not mistaken.” 

“Hmmm, cute.” Max had stood and was proudly displaying her massive cock and balls. “I’m probably pushing six and half feet on this baby.” 

“Why don’t we make it official?” I suggested. We were in the right room already. The girls agreed and we walked over to the measuring station. 

Max had grown to 10’1” over night. 

“Only 2 inches?” She pouted. 

“Babe you’re over 10 feet tall, it’d take two full grown men on each other’s shoulders to match you.” I was still sitting on Jenna’s shoulders and was still several feet below Max’s eyeline.

“Yeah I know, I just wanna be even bigger!” She said, smiling.

Once again it was up to Jenna to measure Max’s cock. After being soft in her sleep it had almost immediately become erect upon waking up. 

“Good lord….” Jenna whispered before reading her findings. “You’re 83 inches Max. 6 feet 11 inches long…” 

“Mmmmm, I don’t wanna stop until even other futa can’t compare….” She was breathing hard and I could tell that she was having trouble holding back. This had become more and more of a problem in the past few days. Even brief mention of her growth caused her to come nearly to the edge of climaxing. So far her willpower had won out but I wondered for how much longer. 

When it came time to weigh Max Jenna handed me over to sit on her chest. I fit pretty well in between her breasts. I leaned forward to get a good look at the scale. 

“Subtracting 30 pounds for me you are….867 pounds, Jesus.”

“My turn!” Jenna exclaimed and as she hopped on the scale. I looked over Max’s cleavage to read the number. 

“294 pounds. Almost 10 times my weight.” I stated. 

“Man, I’m gonna need some new clothes!” Jenna giggled. She wasn’t wrong. Her bed sheet was now woefully small for her frame and the few clothes Max had ordered earlier in the week weren’t fairing much better. 

“Wanna go shopping?” Max asked.

“Can we!?” Jenna jumped up and down in excitement. 

“Of course! I need some new clothes as well. And don’t worry, it’s perfectly normal for growing futa’s to go shopping in the nude, at least around here.” 

“Yaaaaay!” Jenna yelled gleefully and gave Max a hug. I was still sitting in between Max’s chest and Jenna’s head was just level with my own. Our faces met for a brief moment. Jenna looked at me silently and then leaned ever so slightly forward to kiss me. I was taken aback to say the least. Max didn’t seem to have noticed and was fully invested in returning Jenna’s hug. Jenna’s lips and my own were locked for the duration of the hug and when she pulled away she immediately turned around and made for the stairs. 

“Let’s not waste any time!” She yelled back as she bounded up the steps. Max began walking after her completely unaware of what just transpired. Though I’m not sure how she’d react even if she were. The three of us had built a very intimate relationship and the lines between sibling and lover were blurred beyond recognition.             

Max’s Stats.

Height: 10’1”

Weight: 867 Lbs

Penis Size: 3’6” flaccid, 6’11” erect.

Testicle Size: Oversized bean bag. 

Jenna’s Stats.

Height: 8’2”

Weight: 294 Lbs

Penise Size: 18” flaccid, 28” erect.

Testicle Size: Watermelon.       

Trevor’s Stats.

Height: 3’1”

Weight: 30 Lbs

Penis Size: <1’ flaccid, 3” erect.

Testicle Size: ping pong ball.