(Don't Have to) Twist My Arm

The following story about a switch in a poly relationship contains alchemical potions that causes several kinds of growth. If you are not into women growing thick penises or becoming quite muscular, this story is probably not for you.

*****

Yuuki woke to the feeling of her ear lobe being nibbled on as thick fingers toyed with her nipple. From how much bigger she felt in her lover's grasp, some of the effects of her formula must have lingered. Hopefully for good.

Half awake, she ran her hands over her thighs and stomach. The feeling of her muscular core made her shudder with excitement. While her abs were not as inhumanly defined as they were a few hours ago, she was definitely far more fit than yesterday morning.

She rolled over to look at Sage and got caught up the minty scent of her shampoo, which was overwhelming thanks to the sheer volume of copper curls. Her lover continued to tease her nipple, rolling it between her thumb and forefinger. As she did so, the red head leaned over to nibble her neck.

Yuuki felt a throb between her legs. Nothing like last night, nothing phallic, but still more intense than ever before.

"Mmm didn't you get enough last night, pet?" she asked, brushing her hair back.

Sage's pale, freckled face split into a grin, her hand trailing down to grab Yuuki's considerably bolstered ass. She bit her fat bottom lip as she looked up through her lashes. "No, ma'am, I did not," her submissive purred. "Would it be possible for me to get more before tonight?"

"Not right now," she said pulling the redhead into a kiss. "I want to save some my formula for Caroline. Besides, I don't feel that against my legs anymore..."

"Aww, you mean it's gone?" Curious hands moved down her body towards her center. Sage's fingers searched for the formula's surprising and unintended side effect. Although she did not find the thick, meaty cock which had sprouted from Yuuki's clit the night before, they were both surprised to find out just how big the organ still was-and how sensitive from the way her body tensed from just the slight touch.

"Wow, that was intens-oh!"

Sage's fingers slid over her button deftly, her middle digit slipping down between her lips. Yuuki realized as she clenched that it was not just her clit that was more sensitive, everything felt far more sensation.

Gripping her submissive's wrist, Yuuki pulled her hand away. She was losing herself in the excitement. She needed to stay in control of the situation.

"Why were you playing with me just now?"

"It seemed like Ma'am needed some more attention," said her red-headed submissive as she got into her role once more. "I was just..."

"Acting without permission?"

"Yes, ma'am. I just go so...excited. Last night was amazing. No guy's ever fucked me like that."

"Well, if you're good. Caroline and I will use you like that even more tonight."

"I would love that, Ma'am."

"I'm sure. Now, would you be so kind as to help me find out just how much more sensitive I am down there?"

Sage nodded and once more pressed her fat lips to Yuuki's her neck before starting to head downwards. With her bottom kissing down her fit body, she cupped her boobs to confirm just how much new heft she had left over from her growth spurt last night. Scooping them up, she got a feel for just how much of her gained mass remained-quite a bit actually. Purely by size, they had to be twice as big as before. No small feat since she had barely fit in a large sports bra before.

As Sage nibbled around the her vulva, Yuuki's head rolled back. When her submissive finally started to suck on her labia, she could have sworn she was suddenly orbiting the moon. Her ability for coherent thought fading, she tangled her fingers in the other woman's long hair. "Yes...that's it, pet. That feels wonderful..."

-*-

Seeing both of her loves in one day was always a roller coaster. Where Sage was more experienced and gleefully bottomed, Caroline was a bit of a rookie, but enthusiastically topped. It was exhausting switching in such a short span of time, yet rewarding. Yuuki loved the relationships she had with both women and honestly could not see herself without either of them. There was just something about each of them that made her feel whole in different ways.

As much as Sage enjoyed teaching, Caroline enjoyed learning. She was always researching, trying new things, and then getting feedback from her more experienced lover. Tonight, she was experimenting with controlling wardrobe by having Yuuki cook dinner in just an apron and thigh-high tights. Yuuki couldn't help but notice both articles of clothing were on the small side after her growth spurt last night.

There was one thing both women shared, and that was their height. Both Sage and Caroline loomed over Yuuki's demure five-four frame. Though their build were quite different. Her Irish partner was burly, her height complemented by width. In contrast, her partner with Caribbean roots was willowy, her long limbs covered in colorful art.

While Yuuki was cleaning up the leftover flour from cutting made from scratch biscuits, Caroline came up from behind and dragged one of her larger strap-ons against her butt. It was likely the double-ended one.

Yuuki squirmed. "I need to get these in the oven in twenty minutes if you want to eat dinner at five exactly, my Lady." Even so, she stood on her tiptoes and offered herself.

"An' I need relief more than I need food right now, love," her dominant responded, tugging at her shoulder length hair. "There's something about you tonight that's jus'...driving me crazy. It's like you suddenly got even hotter."

Yuuki bit her lip, it was not like she was hiding her changes, she was stark naked after all, but she had not told Caroline about them yet either. She was honestly surprised her partner had not noticed the significant bump to her bust size at the very least. It was not like she wanted to keep them a secret, she wanted her dominant to experience the lasting effects before broaching the topic of taking her formula ahead of their first threesome.

There was a squirting sound, then the hollow thud of the half empty lube. Her dominant pressed against her center, sliding the phallus against her mons, spreading her outer lips wide. The stiff rubber hit her clit and Yuuki gasped as lightning rushed up her spine. She collapsed to the counter into her folded arms. Her newly enlarged boobs slid off the floured counter to hang against the edge.

"Was Sage that good to you, love? You're never this responsive."

"More than I can express, My Lady."

"It's like there's something different, but I can't put my finger on it, but I want to put my dick in it."

Caroline lined up for her thrust and gripped Yuuki's hips. She was both pushed and pulled on, the half-inch thick toy pressing insistently. Being penetrated was almost overwhelming with her new sensitivity and Yuuki was already gasping like they had been going for twenty minutes. She could feel an abundance of her glit running down her legs, lubricating the large rubber cock.

"Oh? Is my girl loving this?"

"Yes, My Lady. Please, fuck me."

Caroline began to thrust slowly and Yuuki's gasps became moans and begging almost at once. Caroline accelerated, each impact now making Yuuki's boobs hit the counter and leave floured imprints.

"Ah! Yes! Yesyesyes!"

All of sudden, Caroline stopped.

"My Lady, why did you stop? Was I not pleasant?"

"Oh, more pleasurable than ever. Which is why I am not continuing until you tell me how you got your body so into overdrive."

"A formula I made...It was, uh, it was just supposed to be a protein boost, but it seems to be far, far more."

"Oh, you very naughty girl," Caroline said, matching each word with a slight thrust. "Keeping such a discovery from me."

"It was not my, ummm, intent, My-My Lady." Yuuki stammered as Caroline resumed her pace. "I was going to, AH!, going to talk with you about it at, mmmm, dinner."

She managed to finish her sentence just before her words once again became gibberish as her entire body clenched in orgasm.

"Well then," Caroline said as she pulled out. "I best not hold you up."

It took Yuuki a while to get the rest of dinner prepared as her legs trembled. The whole time, she could see Caroline sitting at the table. She had put a shirt back on, but was still idly stroking the eight inch dildo sticking out of her. What would she look like after taking a dose of the formula? Would her cock be that big? Would it be bigger?

How long had it been since she fantasized about a partner with an actual dick? She tried to think of the answer as she finished the eggs. An answer eluded her even after putting the plates of breakfast for dinner on the table. Maybe the answer was never?"So what's this formula you've got an' what's it do?"

"The goal was a supplement to take after a workout to help the body process protein. What it seems to do however is something far more impressive."

"And that is...?"

"Well, you said I felt different."

"I wasn't sure how much that was just us not having seen each other in a couple weeks."

"I've grown a lot in the last twenty-four hours," she said, hefting her boobs.

It was the first time Caroline seemed to notice as she gasped. "You're right! Holy shit, how'd I miss that?"

Yuuki crossed her arms under her bust. "Perhaps it's another effect of the formula?"

"Are you tryin' to say you made a formula that not only makes you grow, but also hides that growth? Just want did you make it out of?"

There was a pregnant pause as Yuuki thought about her answer. "Let's just say it's quantum and move on."

"Okay...so what? Why not tell me?"

"I wanted you to see what the lasting effects looked like before I offered you the opportunity to have a dose."

Caroline mouthed the words have a dose and then pursed her lips and furrowed her brow. "Are you saying you wish I was busty?"

"That's what you got out of that? No, not at all. There's a, um, side effect to taking the formula that I think you'd be interested in more than any lasting changes. I wanted you to know though before you just took the formula for the temporary effect."

"Temporary effect? Spit it out, woman. What does this formula do?"

"IT GIVES YOU A DICK!"

"Oh," Caroline said, blinking. "Um, yeah, I can see why you would think I'd want that." Her gaze drifted to the dildo on the table, then down to her naked lap.

"Shall I pour you some?"

"I, well-you know what? Yeah. That way I can go to town on you and your girlfriend later."

"I'm sure she'll enjoy that. I intend on taking some more myself, since I sort of promised her some double teaming."

"Sounds like a wonderful evening, my pet. Now, go get the formula."

Yuuki went to her room and retrieved the case of vials. The first was half empty and she planned to give that to Caroline. When she got back downstairs, her girlfriend was finishing up the dishes. She moved to help, setting the case on the counter as she did so.

"So how much did you take?" Caroline said, handing her a dripping wet plate.

"Half a vial?" Yuuki dried it and put it back.

"What's the max I should take?"

"Probably a full vial."

"Then that is what I want."

"Y-y-you're sure? Why not take half first?"

"We both know I'm going to take as much as I can, why delay it?"

"I guess that's true..."

They finished the dishes and Yuuki fished out a full vial. The blue fluid swirled in the glass. She uncorked it and Caroline took it from her with trembling fingers.

"Well, bottoms up..."

The liquid went down in a couple gulps. A single drop ran down Caroline's cheek and neck. As Yuuki followed its descent, the changes were already happening. Only, Caroline was bulking up far more than Yuuki had. Already her pectorals were bulging, dwarfing her barely-there boobs as thick cords of muscle rose against her skin. Veins rose from her shoulders and biceps as they pulsed larger and larger, her arms growing wider by the second. Her thighs and calves were growing, too, as her quads swelled larger. Most surprising however, were the audible stretching and grinding noises as her already long frame grew further.

Caroline dragged her hands down her body as her moans grew louder and deeper. Her fingers rose and fell over abs that were getting more and more ripped as she moved towards her pussy. Already her clit was starting to poke out from between her legs. She gripped it with one hand as it reached as size comparable to an average erection and began to jerk even as it swelled larger.

"So...so good!"

Movement under her cock caught Yuuki's attention as a pair of balls emerged from Caroline's pelvis in front of her vulva. That was certainly different and promised to keep getting more interesting. Both her dick and her gonads continued to inflate, her skin stretching tight and shiny as the formula fueled transformation raged within her. Six inches. Seven. Eight. It rivaled even her largest strap-on. Her tight sac hung a third of the way to her knees now. Copious amounts of testosterone flooded the rest of her system. Already she was starting to leak thick white fluids as her absurd gonads start to do their work. The thick veins wrapped around her shaft pumped quart after quart of drug laced blood into her new sex, slowly forcing it to an impossible size.

The male hormone's presence in Caroline's system only seemed to heighten the formula's growth potential as her muscles surged larger from head to toe. They were swelling so big, it was like new muscles were growing in to support the bulk. She was miles more muscular than Yuuki had been and probably even considerably more built than any professional bodybuilder-male or female.

Her cock was truly massive now. It had not gotten much longer, but was increasingly fatter, as if echoing the thickness of her arms and legs. It had to be bigger around than a soda can. Its skin was deep red from the sheer volume of blood needed to make it hard. It was twitching with each heartbeat, rising and falling nearly four inches as it swung around despite her hands near the base.

Caroline's jerking grasp began to slide as the precum lubricated her movements. She stroked furiously, groaning the whole time. Yuuki could almost hear her heart beat. The flow was becoming a steady stream that was splattering the floor. Finally, Caroline screamed and a torrent of cum burst forth as her balls pulled tight to her body. The blast hit Yuuki full in the face, painting her white. They both sank to their knees, gasping and reaching for each other.

"Okay," Caroline said. "A full vial is way too much."

"I dunno," Yuuki said as she dragged her fingers around the cum coating her boobs. It seemed to shimmer with blue. As she rubbed, it faded into her skin like lotion and she felt a familiar tingle. She licked the rest off her fingers and shuddered. "I just hope Sage can handle us both..."(2602)