That was when his son Josh came in. "Whatcha doin' Daddy?" "Josh... Hmm..." Jonathon looked back to the Chronivac and looked up Josh's profile. Sure enough, an exact replica of his son was shown on screen. "Daddy...?" John asked, slightly worried that his Dad wasn't saying anything. "Oh, sorry son. I just want to try something out." "Try what out?" "Hmm... let's see... What would you think about being older?" "Oh boy, would I ever!" "Well I think this thing might just be able to do that." Jonathan hit the age slider and doubled Josh's age to 24. The replica changed to match and a behemoth of a man was in the once scrawny 12 year old's place. "What?! No way..." "Probably not, but it can't hurt to try. Take your clothes off just in case." "I don't know, Daddy..." "Don't be afraid. I'll be here for you all the way." Josh hesitated for a little bit, but with an "Okay..." he began to do as he was asked and stripped down to his birthday suit. He awaited his father's instructions as he covered his modesty with his tiny hands. "Okay then. Here goes... Nothing!"
Jonathan hit enter changes and a beam of light hit Josh's body. "Woah!" Josh let out. "Wow! You okay there?" "Yeah... It tickles, really..." The light soon faded, leaving the room the same as it was before. "You feel anything, son?" "Umm..." Josh removed his hands from his wiener and patted his body down. "Nope... Nothing..." "I see... Oh well... I thought it was a scam from the start." Jonathan went to turn the Chronivac off, when it happened. "Burp!" Josh let out a huge belch. "Oh... Excuse me... Umm..." Then Josh rubbed his stomach. "Josh...?" "Ohhh.... umm... I feel funny! Daddy?!" As the two wondered what was happening, Josh fell to the ground on all fours. "Josh?!" Jonathan rushed to his son and rubbed his back. "Ohh... Daddy! My body feels hot! Gahhhh!" Then Josh spasmed. Then again. And again." "Josh?!" Jonathan just repeated as his son's body started to change. It was getting bigger. "Ohhh... It burns!" Josh yelled out. His voice sounded a little deeper than before. That was when Jonathan noticed that Josh wasn't just getting bigger; his body was getting older. A slight stubble formed on his face and his Adam's Apple protruded more and more from his neck. "Ohhh.... Daddy! Daddy!" Josh called out to his father several times, each time his voice got even deeper until it was unrecognizable as a 12 year old boy's. Josh looked to be about 15 now.
"Gah!" Josh spasmed again as he lost his balance and fell onto his backside. Jonathan had a full view of his front now. Josh was sporting visible chest hair and more body hair was coming. It formed a link from his chest to his groin. Jonathan watched in shock as his son's penis doubled in size. "Gah!" Each spasm Josh took made it even taller and thicker. It pulsed outwards and up fully erect. "Gah! Daddy?! My pee-pee feels weird! I want to touch it, Daddy!" "Um wow... Uh, go ahead...?" Jonathan didn't know what to say to that, so he just told Josh to take care of business. Josh fumbled for his erect cock and grasped it with one hand. He then started to pump it up and down. "Ah,ah,ah,ah,ah,ah!" Josh let out several grunts as he jerked himself off for the first time in his life. As he did, his body muscles started to come in. His arms and legs doubled and then tripled in girt. His flabby pectoral muscles hardened and rose up like yeast, his nipples just as erect as his dick. With his other hand, Josh fondled his nipples as well. Just below him, his abdominal muscles hardened and rose inividually. "Two, four... eight... Holy shit!" Jonathan exclaimed as Josh gained a ten pack. He looked to be in his early twenties, which meant he was close to the age Jonathan had set for him.
"Ah,ah,ah,ah,ah,ah... Daddy! Daddy!" Jonathan watched as Josh's behemoth of a cock vibrated. He was approaching his climax. "Daddy?!" "Holy... Um... It's okay, Josh! Don't fight it!" "But..." "No buts, mister!" Jonathan ignored his son's prostrations and flicked his penis. "Ahhh! Daddy, noooooooooooooooo!!!!" And with that, Josh's dick erupted with hot, thick strings of cum. Jonathan moved out of the way as Josh soiled his upper boy with his freshly made man spunk. Some got into his mouth and Josh could taste the saltiness of his own ejaculate. A few more seconds passed as the eruption of Mt. Josh finally started to subside. "Ah...Ahhhhhhh..." Josh let out a long moan as he crossed his arms over his eyes in embarrassment. Then a few seconds later, his penis started to shrink, albeit to a still massive size. Jonathan walked back up to his grown up son and offered his hand. "Welcome to Adulthood!" he said. Josh looked at him in a mixture of thankfulness and embarrassment for what had happened to him, but eventually took his Father's hand and was pulled up. He and him were now eye-level (Josh was slightly taller). Josh gave himself one more look down and welcomed his new reality.