Ty wished for Dustin's wishes to be granted, and they were, except they were all a bit muddled by wanting a few too many things at once.
Dustin's wish for himself was simple: He wanted to be the tallest, most masculine, best hung guy in the room, which would have been a fine wish, except that he was still feeling sorry for Scott and Jeff, and was wishing that Scott would grow a couple feet taller and not look like a pituitary deficiency case, and likewise that Jeff would get a boost of testosterone and get more developed, not having noticed that Ty had already wished these things for them.
So what happened was that Scott, rather than having his growth stunted at age ten, instead retroactively got a massive surge of human growth hormone, shooting up to almost nine feet tall, but still with the cock and balls of the average 19 year old, while Jeff instead suffered a massive testosterone surge, his muscles bulking up insanely, body hair growing up one side and down the other until about the only hairless place on him was the growing bald spot on the top of his head. Meanwhile his balls swelled to the size of grapefruit and his cock grew to match, hanging down slightly past his hairy knees.
"GOOD GOD!" Jeff rumbled in a basso profundo, his already deep voice having dropped about five octaves.
"Yeah," said Scott, looking across at Dustin, who was now nine and a half feet tall, half a head taller than Scott himself, but hairier and more muscular than Jeff, with balls the size of honeydews and a cock down near his ankles, since it had been insane even before his testosterone rush. And the top of his head was completely bald, not that anyone in the room could look right down on it.
"OOH YEAH," rumbled Dustin, lost in pleasure. "I wish my girlfriend could see me right now..."
With that, he promptly disappeared, off to his girlfriend, wherever she was at the moment.