"I feel great!" Timmy said giggling.
Jamie stood staring at the new man his once seven year old brother had become.
Timmy was exploring his new body in the meantime. His large muscular hands caressed his pecs and abs, marveliing at the firmness of his body, his large biceps flexing each time he moved his arms.
He then discovered something he'd not really paid attention to before.
"Jamie! What's wrong with my pee pee, it's huge." Timmy hefted it in his hands, even using both hands the head dangled over.
Jamie gulped. "Well... Timmy... as you grow up your... pee pee grows too."
"It feels... funny." Timmy laughed and watched as his penis began to inflate. "Wow... does yours do that?"
Jamie nodded slowly, his eyes transfixed on the enormous man meat.
"Let me see." Timmy said stepping forward and yanking his brother's joggers down. Jamie tried to cover up but Timmy batted his hands away. "Yours is... so small? I thought, you would be bigger."
He seemed disappointed then he smiled brightly. "Guess I'm bigger all over. Bigger than my big brother! Ha, you're my little brother now Jamie, you have to do as I say now."
"It doesn't work that way Timmy... I am still older."
"But I'm bigger... and stronger!" He giggled and grabbed Jamie's penis, shaking it a little in his huge hands. "Who's in charge J?"
The movement and sensation made Jamie shudder. "Ahhh... mmmm, stop that Timmy... mmm you are... ah... you are."
"That's right... why did you make that mm noise?"
Jamie blushed and lowered his head.
"Remember, I'm bigger I can make you tell me now." To Timmy this was still a game and funny.
"Well, when you're older do that to your penis... your pee pee feels good." Timmy looked at his large organ, now hard and the head showing, all shiny and red.
"Really?" Timmy shook his penis and giggled again. A strange deep giggle. "You do it to me."
Jamie took a step back. "What? No?! Timmy that's wrong."
Timmy took a step forward, his cock swinging. "Do it. Little brother."
Jamie was shaking, partly out of fear, partly with excitement. He reached out, his hand trembling and grasped his brother's penis. Timmy moaned. "That's it, do me like I did you. I wanna.. mm feel it too."
Jamie began to pump the large organ as he had his own much smaller one many times.
Timmy rocked back on his heels in time. Jamie's rhythm increased. Somehow he was enjoying this himself.
Without thinking Jamie leant forward and engulfed Timmy's cock.
"OH! Oh wow! Oh!" Timmy bellowed and grabbed Jamie's head instinctively.
Jamie sucked and licked for a full minute and then Timmy came. What felt like gallons of cum shot from his little brother's spasming cock, dribbling out his mouth and down his chin.
"J... Jamie... what... oh wow... what was that? Do it again..." Timmy collapsed onto the nearest chair, his huge chest heaving his cock deflating and resting over his thick muscular thigh.