Caleb felt like he was finally being validated.
After what felt like months of teasing from Dylan and Christy about his lack of romantic and sexual prospects, he was lined up here with a beautiful woman who was about a year older than him (at least his starting age)...though she did seem shyer than what he was familiar with in terms of his concept of college girls. As Caleb took a seat in a beach chair, Beth slowly moving forward and awkwardly kissing him on the lips first, Caleb suppressed the beaming reaction he knew might give the wrong impression. Having sex! I'm gonna have some sex!
He hardly even noticed, as Beth settled on top of him, touching his well-muscled body, that things were not exactly as he remembered them being. While Beth was not yet changing, Caleb was not so lucky. He crested his teenage years right then and there as he became physically 20 years old. Even as Beth touched his pecs, they pumped up a little more, and his abs etched ever so slightly tighter, with his obliques following suit.
He noted that Beth was a rather insecure lover, probably her first time too, and even though Caleb wasn't quite so inexperienced, he decided to just let her have her time. Let her acclimate to his body. For whatever worth that had on this particular beach. She worked up the bravery to really start kissing Caleb - her tongue darting in his mouth as the two lovers enjoyed their time together. She seemed to gasp as she started pressing her hips against her paramour's groin - discovering Caleb's erection.
"E-E-Erection...!" Beth whispered, excited yet also somewhat concerned.
"Yep," Caleb said with as much confidence as he could muster, "This..." He said as his buzzcut grew out a little bit more with his aging to 20, "This is turning me on...pretty nicely. Take your time. Touch me as much as you want."
Beth blushed, the wallflowery woman seeming to really take to that kind of ask before really pressing herself up against Caleb. The young man chuckled and then gasped as he felt Beth's eager but inexperienced hand start rubbing against his cock, while the other studiously informed her of the well formed nature of her partner in this public act. When Caleb thrust into her hand, she seemed to realize what that meant; "Ohh...you...you like tha---oooohhhh..."
He returned the favor adeptly well, one of his own hands reaching down to start touching her neatly shaved pussy. She gasped on top of him, and knew in that moment she had to have him. After all, what Claire said was the truth - before they even showed up to the island they'd shared a supply of pills among themselves that would delete any chance of a consequence to a solid week of entertainment on the island, enjoying as many men as they wanted.
And for Beth, someone who grew up with a stringent and often choking experience of religious upbringing, this was especially potent. She'd been shy and painfully so in college. Now, with Claire, the ever ebullient party girl, the two were keen on helping Beth find her first boyfriend on vacation. And that was looking to be Caleb.
What a man he was turning out to be!
Caleb for his part groaned as he felt her hand really get accustomed to his sensitive spots. She was new to this, but fuck could she jerk him well. It almost felt like his dick was getting even bigger. That was because it was - thickening and growing more potent as he came of age as a 21 year old, though not quite cumming yet. He wasn't that inexperienced. Beth on the other hand hit her first orgasm of the evening as Caleb's adept hands cupped her breast and rubbed her clitoris.
She let out a thoroughly immodest screaming orgasm - her panties soaked as she rested on top of Caleb. She knew in that moment she could not go back to the way things were before. Beth swore as she looked at Caleb that the young man underneath her looked somewhat more rakishly handsome than the nerdy swimmer she knew before. His muscles tighter, stronger, and a good deal brawnier. And was his hair a bit thicker? Well, she loved what she saw, and in that orgasm-hazed moment she decided she'd just go with what felt good.
And what felt good right now? Having Caleb thrust that big cock into her pussy. Sure her dad would be furious if he knew she was so deflowered, but right now Beth did not care in the least what her father wanted for her marriage options. She was a woman, she had wants, and needs, and that fucker was a million miles away. She whispered in his ear, "It's...it's good now...it's good. Please. Put that cock---uh." Her speech failed at that crucial moment as she realized what she was asking, "Put it...it...mm, put it in me."
"You want me to fuck you?" Caleb asked jovially, subtly flexing larger biceps than he usually had as he leaned back following Beth's orgasm.
"Yes...God yes...!!" Beth answered.
A rearrangement occurred on the beach chair, and Beth stripped fully, letting Caleb see her nude breasts and tight pussy. She looked up, and smiled - thus missing Caleb's sex hungry smirk and the sight of him aging to 22. Caleb's ass grew larger, stronger, becoming more of a bubble in his swimsuit. He groaned at the feeling, so tight in his rear, and didn't even see his quads grow more prominent, nor did he note the slight bit of facial hair starting to come in on his face. Caleb's shoulders broadened a bit as he moved in.
It took him a moment to get his cock in there as he tossed off his swimsuit, cursing the thing mentally and deciding he needed something bigger, and he swore his dick was really looking bigger right now. He just figured he was especially turned on. Before long, Caleb pressed it in successfully, his face awash with sweat and exertion as he started thrusting away.
Caleb was rewarded by fresh moans and even screams from Beth. She knew she was going to likely bleed, but the sheer intensity of the sensation was worth it. The knowledge she had finally had sex with a handsome man was worth it. After being sequestered it seemed for so long, she had done what so many other women had done. Caleb's thrusts began to speed up with the strength given by his newly aged and muscled up legs and ass.
She was absolutely quaking under him, her hands roaming on his body. Absolutely loving, it seemed, his chest, his abs, and his shoulders. "Ohh Caleb! You're so ripped! You're---you're so sexy! Oh---Oh! Caleb flex for me Caleb, please--!!" Well, if the babe wanted it... he figured there was no reason to not. He still thought of himself as just a tight, toned swimmer and a nerd otherwise. So he was slightly surprised when his flex for her in the middle of their coital experience brought up bigger biceps than he remembered - broader, stronger and more boulder-like shoulders, and powerful pecs he certainly didn't remember---
But Caleb was right now having sex with a beautiful woman, and he figured he could rationalize or figure out what was going on with that after he was done! His breaths came hot, heavy and frequent as he gripped one of the beach chair handles with one hand, and her breast with the other, "Ohh fuck babe, oh fuck babe...you drive me wild!" Caleb could feel his hair swaying with him as he fucked her, which couldn't be right - he mostly had a buzz cut after all - but again he didn't let that get in the way.
The 23 year old stud - now looking for all the world like a wild haired, muscled beach bodybuilder - was thrusting away with a cock he had little experience with. Especially in its larger, more potent state. Even as the shaved off body hair started returning a bit on his chest and groin, Caleb gasped, "Babe---Babe you sure? I'm---I'm close. I'm gonna cum soon...fuck you're tight...fuck!!"
She gave Caleb his answer in the form of wrapping her legs around the small of his back. He gasped as he felt her pull him slightly further with that maneuver. "Cum---cum for me, you big, ripped adonis!!" Beth almost screamed.
Let her think I'm some kind of huge muscle man, Caleb figured. I'm getting to finally experience real, total sex.
And so both before long felt their arousal peak, and as they surged above and beyond that peak, Caleb felt his words fail him, his eyes glimpsing upward - his ass flexed and fuck he could feel his sphincter clench as his cock pumped and shot its load. In time with that, Beth experienced her own orgasm yet again. The sheer energy and force of the coupling left both of them just laying there for a time. Caleb with his cock remaining inside her, Beth just luxuriating in finally subverting her family's expectation. She'd gone the distance. She...had sex.
However as Beth started to come down and saw Caleb starting to get up and stretch, she started to realize something was awry here. She remembered a short blond haired, dorky swimmer. Not the gloriously muscled beach bodybuilder currently working out the kinks in his muscles from that kind of an intense fuck session. Even as she knew she should be more alarmed, she registered he was even taller than before - about six foot four inches in fact - and he looked like he'd picked up more of a tan, too.
But she could still recognize some slight elements of Caleb from before. So she did not leap to some abhorrent deceptive conclusion. Instead, she decided to approach this slowly. Cautiously. Avoid freaking out the muscle monster currently doing his stretches, "Caleb?"
"Yeah babe?" Caleb answered in a deeper voice than he recognized. He tried clearing his throat, hoping he wasn't coming down with some weird island sickness. He wiped his forehead and swore he could still hear Claire and Luke going at it over where they ended up - at an umbrella, a free towel and their own beach chair. Going by the sound of it, Luke and Claire - unlike the eased in and cautious coupling that ensued with Caleb and Beth - were a rough and intense coupling that openly made their sexual demands keenly known;
"Stick that hard cock in me harder, Luke!!" "You know I got it for you, babe!" "You nasty, buff surfer boys---! Ohh fuck me, fuck my sweet ass!" "You got it babe---I'm your surf adonis right now!"
Beth managed to ignore that and looked at the smiling young man, who still it seemed had not yet picked up on what happened, "Caleb...look at yourself. Something---Something happened. Just...look at yourself."
"Why? Did I get something on my di---" And then Caleb looked, and saw what Beth meant. His eyes widened, and he looked up. Realizing he was totally different from how he was even just two hours earlier. He was not exactly a swimmer any longer. Even his cry of "Holy fucking shit!!!" however did not interrupt the rampant sexual activities of Luke and Claire. They likely just assumed that it was Caleb hitting orgasm or something.
Caleb glanced around frantically, trying to figure out what might've caused his sudden transformation. "What---what the fuck happened to me?" His hands roamed on his body, and despite how Beth sympathized and wanted to help him, she did admit - it was a very nice body he was feeling up.
"I---I don't know!" Beth responded, and started glancing around.
But before they could try and come to any conclusions, it sounded like the sexcapades of Luke and Claire were finally at an end. Husky gasps and oaths exchanged, the two of them started coming over toward Caleb and Beth...and for their part, both partners outright blanched at what they saw approaching.