Hephaustus (his lower body replaced by his shire-centaur automaton) was carrying some unusual looking harness and tack: a form of breastplate or breast-collar that fit around the human-waist horse-shoulder, in a smooth easy "Y" down to just above where the horse-chest began, connecting at the intersection in a large ring holding a central gemstone, and the tail of the Y consisted of a bottom strap running between the horse-pectoral to connect to another T shape underneath the horse-body that ran back up to connect at the top of the horse-back in another T that connected directly to an inverted Y that met the straps coming up from the first Y -- the result being a harness that cinched close but wasn't restrictive, with the central O of the ring sitting right where the human's genitals would be if they weren't a centaur.
"These are a special creation I made for centaurs who want to be able to mate with humans," Hephaustus said. "All you have to do is put them on, activate the magic, and you'll have properly sized equipment for whatever fun you want to have."
'Rick and Jules said simultaneously, "I don't understand. They'll shrink our dicks?"
"No, no," Hephaustus laughed. "They create up front a simulation of what no longer lives there. Without getting in the way of your breathing or swallowing, which would be the case if your human anatomy were still present. A creation in honor of my lovely wife, to allow the centaurs of older times a way to worship her."
"Is this what you meant by 'toying' with them, great one?" Nic asked. Nic and Alex, the sons of Hebe goddess of youthful vigor, had spoken between them in a rapid twin-language, and determined that it was their duty to prevent Hephaustus from doing anything that would disrupt the workings that allowed the Mount Olympus Spa to exist in a way that could be reached from Earth.
Hephaustus laughed, "That would be telling. But I promise that nothing I do will endanger the Bargain."
"What Bargain is this?" Jules asked, while fitting one of the harnesses onto Derrick.
"Is this something we have to worry about?" 'Rick asked.
"Is this a good time?" a woman's voice spoke, and a late-teens/early-twenties nymph with blond hair and an eclectic dress style walked in from the shadowy paddock to the pool of light in which the others were gathered. She gave a frowning squint to Jules, shrugged, and said, "I'm Melissa, the muse of exposition. It is my job to explain it all for drama and comedy."
"So you're like the chorus goat-boys," 'Rick said.
"I'm much cuter than the chorus goat-boys," she retorted.
"Now here's the story:
The Olympians, like many other tutelary powers and entities, were created. We only know them as Those Above, because we screwed up. We thought, 'Hey, let's get a little ego-boo from these mortals and pretend we're their creators and that we're like gods and stuff.' And that was one of several no-nos, along with having sex with mortals and having children. Not OK with Those Above. We lost our connection. Same thing happened with a bunch of others - the Egyptians, the Dain Sidhe, the Aesir and their buds, the Nephilim... most of us forgot everything, and we have gibberish instead. There's a popular story about Babylon and a tower? Well in our version of that story, the tower's fall was because we were on top of it pretending.
Got all that? Good, because what happened after that was really ... sucky. We had the power to enter the world of humans, and it was taken away from us. We were stuck in the back of the collective unconscious of humanity, and it scrambled the hell out of us, some of us turned into things so twisted from what we were before that it was intolerable. Eventually, though, we repented enough that we could hear Those Above, very dimly. Ananke, the incarnation of Necessity, had never lost that power, but she wasn't as obsessively worshipped and never wanted to be. By this time, Olympus was fading in and out of Chaos, disconnected from solidity, only being pulled back when humans learned enough about the original stories to be interested again.
Ananke brokered a deal with Those Above, to allow the Olympians a way to bring their drifting home back into closer alignment with Earth. They wouldn't allow us to go to Earth, but select humans could come among us, as long as we didn't present ourselves as being gods, and we could grant whatever things the humans truly wanted using our inborn powers, but nothing that would make them unsuited for their own world, and except for healing, it would be reverted when they return to Earth from here. In exchange they would allow us to become anchored to Gaia again so we can lend her our power to help fight the damage you humans have done in your world, without the guidance that we should have been there to give. And, we are required to do that."
She pointed to Hephaustus. "YOU, though, have found a loophole. Be very careful that you don't mess things up, or Ananke will make sure you suffer the consequences. There are three known loopholes, and you've already used one of them when Ananke helped grant Jules' wish to be Derrick's identical twin. The second loophole is that Hephaustus' works themselves aren't necessarily magical, and thus, aren't necessarily barred from being taken back to Earth. Be very careful about that, Forge Master. Remember the terms of our agreement."
"Yes, you needn't lecture me too harshly," Hephaustus answered with the winning smile he had used on Derrick in the first place. "I promise that anything I give will only work magic to support Gaia's healing."
She stared for a minute, then shrugged. She pulled out a small scroll, read what was on it two or three times while muttering, and then rolled it back up and stuck it in her belt.
"OK, fine, my work here is done. Carry on with whatever it is you're plotting. Ananke is watching you."
She was gone, as if she hadn't been there in the first place. Derrick and Jules looked at each other.
"You wanted to be my identical twin? That means you weren't before. Thanks, brother," 'Rick said. Jules blushed a bit, and shuffled his four horse-feet around.
"OK, enough of this. Put that other harness on Jules there," Hephaustus directed. His Shire Stallion lower-body had a ring-and-gem like the one from the harness already in place, built in, one of the subtle indicators that it was a mechanism rather than actual flesh-and-blood. (It also had steel hooves, and carbon-fiber skin faintly visible under the horse-hair hide that coated it.)
"OK, this is where we have fun," Hephaustus said. "Do any of you have objection to a bit of healthy copulation?"
Jules and 'Rick looked at each other and blushed. They seemed to be blushing a lot recently, which showed mostly because their human parts had pale, if slightly tanned, skin even though their horse-parts had darker skin. Hephaustus continued, pretending not to notice their embarrassment.
"And by healthy of course I don't mean twins with their twins, which tradition says is an intimate and private thing. Breaking that convention would be most improper. Dionysus might encourage such a thing but it's barely appropriate even when he's performing his 'break the conventions, break the inhibitions' function. You pair up with whichever of Hebe's sons you like best, so long as they're willing."
Nic looked at Derrick and smiled suggestively. 'Rick lifted him up into a kiss and Nic wrapped his legs around 'Rick's human torso, and they began a passionate make-out that both had been considering earlier in the Gymnasion. Meanwhile, Alex had vaulted up onto Jules' back and was kissing him on the neck from behind, when Jules turned around partway showing the tremendous flexibility of young centaurs, to have a better angle for their kissing. Both of the centaurs felt like their hormones were surging far beyond any teenage lust-bomb events they'd experienced before.
They began to enjoy a form of blindness to their surroundings that might be familiar to many in similar situations (minus the inter-species-sentients part, which would be rare on Earth) ... then there was a momentary TWINGE as the part of the harness on their upper backs, which rode along their spine in the small valley of intersecting muscle, suddenly extended near-microscopic fibers deep into their bodies, anchoring in place while allowing thousands of other fibers to move deeper, sliding in, down, around without harming or interfering, to wrap around bone and connect to the nerves on the inside face of the spine, then extending up and along the human spine to create a second set of spinal nerves, connecting up into the brain, down into the horse-like part of the body and out along the primary nerves. They connected to the cluster of pseudo-nerves that had grown in from the gem-ring-harness on their former human groin and there was a fast synchronization, and both centaur-brothers felt a sudden presence there.
A whispered, simultaneous question, and they maneuvered their partners down a bit, so the sons of Hebe and Hercules could rest their quite-erect dicks against the slick gems, and the gemstone face changed, forming an opening that pulled the young godlings' erections inside a hot, slick, flexing tube, while another part of the gem extended out along their perineums, like a vibrating tongue, then sliding bit by insistent bit past their sphincters, in perfect synchronization, then extending inward, growing in diameter and flexing around until they located the prostates, and then the vibrations began in earnest.
Jules and 'Rick were abruptly aware of each other physically, as if their bodies were shared, and a smile grew identically on their faces as they could both feel each of the twin gods thrusting into them, and themselves in the others, and it occurred to them that they had control of whether or not the other would orgasm. They agreed to hold out for a while, because it was too delightful keeping Alex and Nic impaled/impaling them while they writhed in pleasure.
Meanwhile, inside the stable, the groomer whispered to the glowing white stallion.
"Phaethon, would you like to join with me again?"
The horse whickered and nodded, scraping the floor eagerly.
"Then let us combine."
Apollo vaulted as if to mount the back of the sun-steed, but instead, his lower body, and the horse's head, became fuzzy, and blurred together, pulling the Greek sun-god into a centaur-configuration with his lead horse.
'Blessed son of my alternate self, it would please me if you were to take control of our shared body, so that I may use my powers to add to the working Hephaustus is about to perform,' the sun said inside the centaur, and Phaethon agreed. He had been, not completely, but nearly completely, destroyed when he asked his father Helios for permission to drive the chariot, and Helios had given up his power and position to Apollo in exchange for keeping his son alive in the form of a one of the horses he had failed to master in that foolish day. He flexed his body, both horse, and human-like god, and admired the strength and power of it. Normally he would be mating with a mare, or possibly one of his subordinate stallions if they wanted him, but today he would be with a centaur, one of the pair of identical foals that were grown to adult status. He cantered out to the paddock where Hephaustus in his horse-body prosthesis was lining up behind one of the twin centaur stallions -- they were busy doing something with their front-parts and some two-legger gods that he couldn't see clearly. He moved in behind the other one, and lifted aside the tail, and the centaur looked back at him, eyes widened, and nodded, bracing his hind legs slightly apart. He teased its chute, reaching down to lightly stroke the testicles where they rode below. But one of Hephaustus' bronze maidens stepped forward, helping him into place, and applying a bit of lubricant to the tight sphincter as he slid inside, to the deep moans of the centaur. Meanwhile, Hephaustus was doing the same thing with his centaur.
Derrick felt something shove into him from behind, a shock at first then intensely pleasurable, and he opened his eyes to see a brilliantly white, massively muscular centaur-stallion sliding into Jules in the same way. They immediately felt the extended connection and they were both being fucked from behind, while something below them was sliding onto their horse-dicks, not an actual mare or stallion, but something tight and slick that engulfed them and began a tingling vibration around their shafts, causing them to quickly engorge and erect, flaring them at the end, and that felt astonishingly good.
At this point neither of them could have said three words coherently, and Nic and Alex were beginning to feel orgasm building, but the devices they were attached into stopped them short, holding them on the edge, while Hephaustus built to his own, without the limits. He held Derrick and Jules on-edge, and they held Nic and Alex on edge, for ten minutes while they came the first time, then stayed in them while their cum produced the changes that they had intended, then another ten minutes for a second dose, and then they changed partners, with Phaethon-Apollo moving to 'Rick and Hephaustus moving to Jules, then another ten minutes of fucking before all the twins were allowed to explode in their own orgasmic bliss, and the supercharged essence from Nic and Alex made further changes.
The sun-stallion relaxed a bit, sighing happily, and introduced himself to the twins.
"Phaethon and Apollo, it's been a pleasure to meet you both."
Jules was slightly delirious and Derrick wasn't much better, and they half-drunkenly laid large hugs on the sun-steed, and on Hephaustus, while exhausted Nic and Alex lay across their backs, half-asleep and twitching. The first thing that had changed was that both centaurs had black skin with a faint carbon-fiber hex coloration, and their manes and hair and body-fur over that were cream-white, rather than the mottled chestnut-and-white from before. Their Drum-horse background was still enough that they had enormous "feathers" on their feet, and lush, ridiculous tails that would be expected more on young girl's toys, along with the manes that matched, but no young girl's toy would be as massively muscled as these two. Like most stallions, they had large horse-cocks, but against the expectation, theirs were normal, for horses larger than Shire stallions. Their humanoid halves were much more muscled than seemed possible, but their arms and shoulder-brace had expanded enough that they were still flexible. Their human torsos and faces were not naked, but covered in a soft, short, fur-like coating that matched their horse-coats, absent only in a few places (the palms of their hands being two of them.) Their hands had square iron "nails" and their hooves appeared also to be made from iron, and they had several "gem" inserts over their bodies, most of them no more than an inch or so in diameter. The harnesses were gone completely, incorporated somehow into their bodies. Except for the possibly unnerving gem inserts, they looked almost too perfect physically.
They towered over the human-sized gods, and were even a bit taller and noticeably more muscled than Phaeton-Apollo, who gleefully stroked over their bodies, admiring the handiwork he and Hephaustus had made. The forge-god was a bit disturbed, in fact.
"I might've gone too far," he said. "They're ... well, they're going to have a hard time going unnoticed."
"Nonsense," the Apollo part of the sun-centaur said. "I set it up so the extra stuff will shift outside normal reality, it won't be noticeable, and the world needs more beautiful teenagers."
The two centaurs recovered abruptly, almost as if they were rebooted by that phrase.
"Toyed with, indeed," Jules said to Hephaustus. "What are you doing with the seed you collected from us?"
"That, lads, will improve both the sun-steeds, and possibly the centaur population here. They've become rather insipid."
"We should take these two back to their quarters," 'Rick said, and he realized their voices were past baritone into bass.
"We should." They both touched the small gems on their respective human sternums, and there was a flare of light, and they looked ... no smaller, no less powerful, but the gems and the metal on their bodies, and the carbon-fiber of their skins, was no longer visible.
"Thank you," they said, and left the brightly glowing centaur stallion and the half-machine centaur stallion in the paddock with the bronze-colored handmaids.
"Polite fellows," Hephaustus noted.
"I'm still horny," Phaethon said.
"Well get thee behind me," Hephaustus grinned. "Aphrodite is playing War games tonight and I want to get fucked too."