When Derek grabbed what looked like a mottled rubber tube, Jake had to force himself to repress a laughter. "Dude, I think that's a horse cock!", he exclaimed.
Derek looked surprised by his own choice. "Really?", he asked, staring at the thick, long shaft in his hands. "I don't even know why I picked this up, of all the things here... But it looked like it was the right one for me".
Jake shrugged: if Derek was satisfied with his choice, who was he to stop him? "You should try that on, then. I'm pretty sure it will give you a horse cock, if that's what you want".
The other skater grinned widely. "Well, what's not to like? Horses are majorly hung, right? I mean, look at the size of this thing!". He then looked at Jake, a strange, indecipherable expression in his beautiful eyes. "But joking aside, dude... Since you've given me a taste of the changes this shop can do, I crave for more. I want to become something the world has never seen before; and while there are tons of skater jocks out there - even if only a handful have perfect bods like we two have - one that is literally well-hung like a horse? No such luck". Derek lowered his gaze. "If that's okay to you, bro".
Jake kissed his friend and lover on a cheek. "If this is what makes you happy, I have no objections". Honestly, the idea of his boyfriend becoming a freak of nature with a giant animalistic cock was turning him on big time. "Let's hit the Change Room, then".
The door was still locked, though; and from the other side, deep, baritone moans could be heard. "Guess that flea from before is going through a huge upgrade in there", Derek snickered. His hands kept rubbing the latex tube, like he was giving it a hand-job, and Jake could feel that his bro was trying with all his might not to drop his pants in the middle of the shop and get a new cock there and now.
Finally, a couple of minutes later, the door unlocked. What came out of the Change Room was a behemoth of a man, easily 6'6'' with a glorious, bushy black beard and a bald head shining under the neon lights. His chest was sporting a huge set of pecs and a muscle gut, and a deep, thick pelt of black hairs covered his from neck to toe. With some leather gear and a cigar in his mouth, he could've been the perfect bear daddy, wet dream of all the chubby cubs in the world.
The colossus looked down at Jake and Derek, who were staring at him in admiration. Strangely, he seemed embarrassed, and scratched the back of his neck with his sausage-like fingers. "Um... Sorry, guys, I left something... well, something mine in there. I'll go ask the store clerk if I can find something to clean the mess...".
Jake winked at him. "Don't worry about that. Things in there are just going to become even messier", and Derek proudly showed him the latex horse cock.
The bear's deep chocolate eyes were impressed and intrigued. "I can't wait to see the results", he proclaimed. "And if you'd like to, even try them...", he then added at a lower tone of voice.
"We'll see", Derek answered, before he and Jake entered the Change Room. As the bear said, the mirror was covered in hot, thick sperm, coating the reflective surface and rendering it useless. Before Jake could realized it, Derek had already peeled off his pants and boxers and placed his erect cock inside the latex tube. "Oh, boy, I can't wait to cum through this baby...", he moaned when the cock started merging with his own body, becoming fleshy and warm to the touch. This time, the change was not as radical as his transformation from teenager to skater god had been: the mottled shaft just became his own, while his balls inflated, becoming huge and ripe. Under Derek's touch, the horse cock quickly became rock-hard: the flat top of it was at the level of his mouth, like it was waiting to be sucked.
"I can't believe I'm saying this, but it looks fucking good on you, dude!", Jake exclaimed, his own dick tenting painfully against his shorts.
"You have no idea, bro. This feels... I can't even describe what I'm feeling right now". Derek's horny face was more than enough for Jake, though. "But if you really want to, you can find out first-hand".
"What d'you mean?".
"I can feel that... I dunno, call that instinct or whatever, but I know that this is contagious; everyone who gets a load of my man juice will sprout a cock just like mine. So", and Derek stroked his horse dick seductively. "Are you interested?".
Jake didn’t need to be told twice: he grabbed the black and pink shaft and started going to town with it, licking the heavy globs of salty precum. He couldn't wait to become a freak of nature like his partner, and he could feel Derek's orgasm mounting under his arms... Until it was too late, and the horse cock fired like a hose, coating Jake's mouth with pure equine spunk. He greedily swallowed every single drop of it, and then sat on the leather sofa, unbuckled his shorts and waited for the inevitable changes to happen. His cock was already hard, and his balls starting to blacken; less than two minutes later a proud, towering equine cock rested between Jake's muscular legs.
"So... Do you think the skaters we create with our feet will get a horsey prick too?", Derek asked. His erection had deflated and he was now sporting a gigantic package in his shorts, that were now looking dangerously close to rip at the seams.
"I... I d-dunno, dude...". Jake's mind was foggy and slow, and he couldn't help but thinking to his new, sexy shaft, still rock hard and dangling in front of his face. "God, this is k-killing me...".
"Want some help?", Derek asked, fondling Jake's black, hairy scrotum. "You sucked mine, I'll be more than glad to return the favor".
What Jake wanted the most, though, was to someone else to taste his juicy meat. He desperately craved to spread the contagion, to bestow on another the gift of horniness and pleasure Derek had given him...