Jake had been tiny up until he was sixteen. Then he had a growth spurt. No, he had THE growth spurt. His childlike frame started to swell upward and outward in every direction. Luckily his birthday was a week after school ended, because the demands of his body were time consuming. When he wasn’t eating he was sleeping, and when he wasn’t sleeping he was jacking off. He didn’t so much as touch a weight, but he still became progressively more muscular. By the time school started back up he was almost unrecognizable. He’d gone from a skinny, androgynous 5 feet to a massive, testosterone-filled hulking beast just a hair over seven feet tall and five hundred pounds of rock-hard bulging muscles. He would spend hours narcissistically flexing in the mirror. And his cock… when he was naked (which was as often as possible) it dangled down to between his knees and was impossible for him to fit one of his massive hands around, and that was when it was completely soft. And below it were apple-sized balls that actually grew to a maximum of twice that size when he went a long time without getting off. He was the talk of the school, of course, but he remained incredibly shy. The only real friend he had was Tammy, his best friend (not his girlfriend, despite what many speculated) since kindergarten. It took a few minutes to convince her it was actually him, but she took it pretty well. When they had parted at the end of freshman year she had been six inches taller than him, with a perfect beach body. Now, despite her being two inches taller, Jake utterly dwarfed her just like everyone else, but her ass and tits were noticeably larger than they had been last year. “Jesus,” she said once Jake had answered a number of questions satisfactorily, “what the fuck happened to you?” “I don’t know,” Jake rumbled, still marveling at how low his voice had become, “After my birthday I just started growing. I was constantly hungry and I was just getting bigger and stronger by the day.” “How tall are you?” “Seven feet and half an inch.” “How strong?” “Honestly, I have no idea. I haven’t lifted any weights or anything.” Images of Jake even more gigantic than he already was filled Tammy’s head. “We’re gonna need to find out, then. And see how much bigger you can get.” “I didn’t really expect you to be this enthusiastic about this.” “Well I’ll miss being taller than you, but otherwise what’s not to like?” She didn’t add that the sight of the massive bulge in his pants was turning her on like nothing had before.
They went to Tammy’s house after school and found that Jake could lift her mother’s van clear over his head, however briefly. At Tammy’s insistence, Jake started working out at a public gym (the school gym didn’t have the multi-ton weights he needed to actually challenge him) with Tammy watching. Over the next two years, he slowly but surely continued to grow. Multiple people said he should join the football team, but he disliked the idea of hurting anyone too much. By senior year he had reached his full size, at 7’5 and 630 pounds, and more than strong enough to hold the van over his head one-handed. Getting through doors was definitely a hassle, but otherwise he loved it. Shortly after his initial growth spurt, he and Tammy had started dating. Their senior year, when they had both turned eighteen, they had sex for the first time, in his bedroom. She jacked him off, opened her mouth as wide as she could, and was just barely able to get his tip in. He came, sending what felt like gallons of semen down her throat until she was forced off and caught what she could of his remaining load in her mouth.
The next week, Tammy wasn’t at school. Neither was her mother, the cheerleading coach. Jake didn’t initially think much of it, but as the week went on he started to worry. She wouldn’t answer any of his texts until Saturday morning, with a simple “Come to my place.”
Jake knocked, waited for a minute and a half, then texted. Tammy’s response was “It’s open. Come out to the backyard.” He squeezed through the front door, walked down the hall to the living room and outside. “Hi, Jake.” Jake almost went into cardiac arrest. Just to the left of the door stood Tammy’s mom and a ten foot tall mass of muscle not only taller than him, but vastly more muscular. Arms bigger than his waist, legs bigger than its arms, a massive twelve pack, no neck, shoulders big enough for him to sit on, everything surpassed him in every way. The figure was naked, so between its shape and what was between its gigantic legs Jake could tell it was a woman. Between the massive, sloping traps that had swallowed the figures neck was a familiar face. “T-Tammy? What happened to you?” “Surprise! We don’t know how, but after I had sex with you, I woke up the next morning starving. I was eating nonstop for days and got bigger by the day, just like you.” She idly flexed a gigantic arm, then giggled. “Well, obviously not JUST like you. Good to see you like it.” Jake only then noticed that he was more turned on than ever, and his cock had torn out of his pants. Tammy giggled again.
Tammy’s mother had always wanted to build large muscles, but had never been able to. With Tammy and Jake’s permission, she sucked Jake off. Over the next week she grew as gigantic as her daughter. Then she realized she could finally do something about the football team getting all the attention. The trio filled bottles with Jake’s semen, and invited the cheer team to Tammy’s house. Over the next week, each girl swelled into a musclebound giantess. Nobody was paying much attention to the next football game.
After graduating, Jake and Tammy got married. From a massive, specially-built mountain cabin they began selling “Jake and Tammy’s muscle mixture for women.” Before long the hulking couple were rolling in money and gigantic musclewomen gradually became an increasingly common fact of life in the United States. Around when they made their first international shipment they found that Tammy was pregnant with an abnormally large girl.
