Andy finished his workout and looked in the mirror. The wet spot in Jesse's joggers was barely noticeable now with all the sweat dripping down his hairy body. Andy looked in the mirror, smiling at the way the sweat stuck to his hairy pecs and dripped down to the hair covering his abs. Nobody alive would have ever guessed he was just 14 years old. Especially not with with his 11-inch cock pushing against his older brother's grey joggers.
Andy left the basement gym and went to look for Jesse. He wanted his older brother to see him all sweaty and hairy. Jesse's car was gone. Andy had some time to get ready for his brother to get back. He didn't bother showering. He liked the stench of the sweat on his furry body. He did raid Jesse's closet again for a jockstrap. He grabbed the biggest one he could find and took off the sticky joggers, leaving them laying on Jesse's bed. He pulled the tight jockstrap over his massive cock. Jesse's had never been this big, so it was a very tight squeeze. The whole pouch was stuffed with one of the most glorious cocks to ever exist. The waistband was being pulled down from the weight of the 11-inches.
Andy went back out to the family room and sat down, his legs spread wide to accommodate his new girth. It didn't take long for Andy to hear Jesse's car pull into the driveway.
Jesse walked into the house, "Jesus," he said, noticing his nearly naked brother. "I know it must be exciting for you to have my dick, but you do still need to wear normal clothes. What happened to my joggers that you borrowed?"
"They're a bit of a mess right now," said Andy. "Especially since I made your cock even bigger."
Jesse couldn't help but look down to see that Andy was right. Jesse recognized the jockstrap, but didn't recognize the cock that was stuffing it full. It had definitely gotten bigger, which just made Jesse angrier. Andy saw the look of anger on his brother's face and knew exactly what to do.
"I had to borrow one of your jockstraps," Andy said spreading his massive, hairy thighs even farther. Hair crept out from the sides of the too-small jockstrap. "Too bad it doesn't really fit. Guess you're just too small."
That was all it took for Jesse's temper to get the best of him, "Listen here you little shit. That's my cock. I don't care if it's bigger now or not. It's mine and I'm going to get it back somehow. And then you can just go back to being the sniveling little twerp that you will always be."
Andy smiled, tilting his back as the feeling of growth covered his body once more. It started with his feet which grew slightly. It worked its way up his calves and thighs which both thickened and lengthened. Andy's abs became more defined and ripped. He pecs pushed out further from his body and his nipples stiffened. His neck and shoulders widened even more as his biceps grew several inches. More hair grew out of his legs, abs, and chest, all the way up to his face, where even more stubble grew. Finally, his jockstrap got even tighter as his cock grew to 13-inches. Andy was easily the biggest 14-year-old alive and he wanted to be even bigger.
He stood up and walked over to his brother who was now at eye level. "Thanks," Andy said in a voice that was much deeper than it was a moment ago. Andy reached up and flexed both is biceps. He was now 6'4", the same height as his older brother. His feet were now a size 13, the same as Jesse. Andy was practically a mirror of Jesse now. With the exception of the 13-inches he was packing.
Jesse turned away, embarrassed. He was mad at himself. It was obvious that Andy was going out of his way to get Jesse to insult him. He couldn't believe that he kept falling for it. It was pretty easy for Jesse to see that Andy now had the same muscles as him. Just one more insult and his younger brother would easily outgrow him.
When Jesse turned back around, Andy had his eyes closed and was standing there with one had massaging his hairy nipple and the other stroking the outside of his jockstrap.
Andy quickly opened his eyes, "We'll finish this later," he said in his new, deep voice, "I've got to go take care of this or I'll explode." Andy turned to head to the bathroom, but before he started walking he reached down and ripped the tight jockstrap off with one had.
Jesse watched the wide, muscular back of his brother and his 13-inch cock swing between his legs as Andy walked towards the bathroom, hand already wrapped around his massive tool.