In the weeks following Sarah’s growth spurt and usage of the GrowTech pills that transformed her from a normal girlfriend into a towering muscular goddess, her relationship with Jacob changed greatly. At first, Jacob had assumed that she would assume a bossier personality and act almost like a dominatrix towards him, but in reality she was always gentle with her boyfriend. It was true that she was more self-assured in her opinions and had developed enormous self-confidence, but that never eclipsed her love for him. Sarah’s main change in personality was a massive increase in libido and sex drive. She practically demanded that Jacob fuck her twice a day, once in the morning and at night. Sometimes they had sex four or five times throughout the day, which proved to be very taxing on Jacob’s body. He simply couldn’t keep up with Sarah physically, which led him to start attending the gym with her.

In her previous growth spurt, Sarah had used up all of the GrowTech pills, so for now she relied on protein powder and the “traditional” way of building muscle. That was fine by her as she felt that if she grew much larger, her life would be significantly complicated since she couldn’t fit in cars or find clothes that were large enough. Those activities were already difficult enough at her current size, which meant Jacob was usually the one driving her around, while she sat in the back seat and put down the passenger seat so she could stretch her long legs. She’d prop her feet up on the dashboard, which distracted Jacob greatly because his eyes would be drawn to his lover’s muscled, bulging quads, and her calves which were each the size of a grapefruit. For clothing, she wore a XXXL shirt and lots of spandex. The fabric stretched to its limit to cover her shapely rear and there was an incident where she split her shorts mid-squat one day, exposing her ass to the rest of the gym.

Sarah had become a celebrity around town and on the state level. She had started an Instagram page with Jacob where they shared their workout journey together, though Sarah was the main driver for the page’s growth. Bodybuilding companies reached out to Sarah to sponsor her to use their products. At first, she was apprehensive, but eventually agreed when she saw how much money they were offering. Soon, she was an Amazonian millionaire, growing more and more famous by the day. That was when the trouble started.

One day, after a grueling workout, Jacob was driving Sarah home.

“I need to start deadlifting more, I feel like my hamstrings are lagging behind my quads,” she said. “I also need to hit shoulders more. The proportions on my arms are getting out of where I’d like them.”

Jacob nodded along. He didn’t understand the workout and bodybuilding stuff as well as Sarah did, but he tried to keep up.

“What are you in the mood for tonight? Chicken and rice again? Steak?” he asked.

“Hmm, I’ll let you choose honey. You haven’t picked in over a week.”

“I could go for a pizza. I know, I know, I’ll get you the meat lover’s one.”

“Thanks babe!” said Sarah, impressed he knew her order. “You’re the best.”

When they got home, there was another car in the driveway, a big red pickup truck.

“Who’s that?”

“I thought you’d know…”

They walked up to the pickup and saw a really strong looking woman inside of it. Unlike Sarah, who had blonde hair and blue eyes, this lady was a tanned brunette, Italian or Latina by the looks of it. Sarah rapped on the window with her knuckle.

“Can I help you?”

The lady climbed out of the truck and Jacob’s jaw dropped. He could tell she was strong, but he hadn’t expected her to be 7 feet tall and massive, rivaling Sarah’s size and strength.

“I’m Tiffany and I think you might have taken something of mine.”

“Um, what?” asked Jacob. Tiffany turned on him, bending down menacingly so that her boobs were pressed in his face. Her hulking muscles tensed dangerously, but Jacob stood bravely in spite of the fact she could beat him into a pulp if she wanted.

“Was I talking to you, pipsqueak?” she asked.

“You’re accusing my girlfriend of being a thief, I think that involves me.”

“Show some fucking respect,” said Tiffany. “You talk big game for a tiny little man.”

“DON’T. TALK TO MY MAN LIKE THAT.” roared Sarah. She spun Tiffany around by her shoulders, which clearly took her by surprise.

Suddenly, Tiffany’s cockiness evaporated. “O-ok, I’m sorry. It’s been a long day.”

“Come inside,” said Sarah. “We’ll talk after you apologize to Jacob.”

Tiffany muttered sorry and then repeated it louder, when Sarah gave her a glare.

The three of them went inside, with Jacob trailing behind the two behemoths. Even though he had gotten off to a rocky start with her, he had to admit that Tiffany was really sexy. She had a bigger butt than Sarah and her bitchy attitude kind of turned him on.

“So, what’s this all about?” asked Sarah.

“You took my pills. The GrowTech ones.”

Clearly, Sarah had not expected to hear that name come out of Tiffany’s mouth, although her size certainly made sense now.

“What makes you so sure she took them?” asked Jacob.

“I mean, fuckin’ look at her! She’s got to be the biggest woman in the world, I should know because I thought I was the biggest until I saw her pop up on my Instagram.”

“There’s no point in lying, I guess,” said Sarah. “I found the pills at the pharmacy I used to work at and didn’t know what they were, so I took them home. The rest is history.”

“Well, I’d like to have them back now.”

“You can’t. They ran out a few weeks ago, that’s why I stopped growing so much.”

“You took all of those fucking pills!? There must have been a few dozen left!”

“I mean, look at me!” laughed Sarah.

Tiffany’s plans had been spoiled and looked frustrated, but after a moment she brightened up.

“I know how we can both grow bigger. My ex-boyfriend was the one who introduced me to GrowTech. He’s a scientist who designed the pills and the pills we took were actually just a prototype he’d produced. Before I took the pills, I was 4’11’’ and scrawny. It didn’t take him long to realize I’d stolen the pills, but by then it was too late and I was on my way to becoming huge. Besides, as I grew I realized that I’m a little less straight than I thought. He came home and found me fucking the pilates instructor from my gym, that was the final straw. I know where he’s living now, I bet he’s got a few more of those pills at his house, he was always taking them home to experiment on them.”

“So you want us to go steal them from his house? I don’t know…” said Sarah. She looked at Jacob to see what he thought.

The truth was, as soon as he heard Tiffany was bisexual, a thought entered his mind. A pretty natural thought for most guys to have -- having a threesome. And not just any threesome, this would be with the two strongest women on Earth. He nodded to show Sarah he was on board.

Jacob drove Sarah and Tiffany over to her ex’s house around midnight. He was going to have to break in because the women were too big to be effective cat burglars. He slipped in through the window and followed Tiffany’s instructions to find the pills. At least he saw two bottles sitting next to a set of beakers and flasks. Bingo! He nabbed them, got out, and drove home.

Back at the house, Tiffany greedily poured a few of the pills into her mouth.

“YES! It’s finally time to grow biggerrrr!!”

Sarah didn’t like the sound of being second-largest, so she palmed a few of the pills as well. Jacob’s dick thumped as all of this unfolded. Soon, he was going to witness two huge growth spurts. He wanted it to occur at the perfect time, though.

“Say, ladies, all of this talk of growing has got me thinking… how about a little cardio?”

He took off his shirt and unbuttoned his shorts and began massaging Sarah’s breasts. He dragged his finger around her nipple, watching it grow erect. He then began sucking her nipple, which elicited a small moan from her lips. She reached her other hand down to her groin and began stroking her clit. Tiffany watched, getting turned on by the second.

“Don’t have all the fun without me,” she purred, before placing her mouth on Sarah’s other breast and joining Jacob in sucking her nipples. His plan had worked, knowing the effect the pills had on their sex drives, all he had to do was bring up the subject and they would be begging him for a threesome soon enough.

Jacob stroked Sarah’s muscular physique, tracing the outline of her rock-hard abs with his finger. He put a hand around her bicep, barely able to reach around half of it. She flexed and he felt a surge of veins pulsing along her muscle. Sarah wrapped a hand around Jacob’s dick and gave it a little squeeze.

“I think you should let the guest eat first, honey,” she said, nodding at Tiffany.

“Mmm, I agree,” said Tiffany, who took Jacob’s dick in her mouth. She slid her tongue up and down his shaft, while her hands fondled his balls. The way she looked up at him with her big brown eyes was so fucking hot. Not to mention the view of her muscles from Jacob’s point of view. That was pretty amazing too. While she gave Jacob one of the best blowjobs of his life, Sarah crouched down and began licking Tiffany’s pussy. In order for it to work, Jacob had to sit on his girlfriend’s back, straddling her like a horse. Sarah was strong enough that she barely felt the weight at all.

“I’m getting close,” said Jacob. “So…close…”

Sarah popped her head out from Tiffany’s crotch and hissed, “Not yet you’re not! You finish when I say so.”

Jacob was used to this. He hopped off of Sarah’s back and stood behind her massive rear. She resumed giving Tiffany head, while Jacob started pounding away at her ass, thrusting in her tight pussy. Tiffany and Jacob locked eyes and seemed to share a feeling, the feeling of loving Sarah. She was greater than either of them and truly was a Goddess. Jacob looked own at her and realized that she was growing, her muscles swelling by the second. She had definitely grown taller over the course of making love. Tiffany noticed it too and sensed growth in herself as well. Her breasts grew fuller and fuller, hanging freely.

After another few minutes, Tiffany started panting heavily and then convulsing, cumming from Sarah’s cunnilingus. Sarah was on the brink of orgasm herself and she sensed Jacob was too.

“Cum for me baby, fill me up with your sperm,” she said. “I want your dick to explode inside of me… mmmm….yes…. Yes! Yes! FUCK YES!!”

Jacob felt a bead of sweat trickle down his head and saw Sarah’s back glisten in the moonlight. He fell off of her and slumped in a heap on the floor. She rolled over, her magnificent chest rising and falling. Tiffany joined them. They lay there silently for a moment before Jacob spoke up,

“So how many of those pills do we have left?”