"I want to be like you." Aaron said almost instantly.
"What?"
Aaron walked up to Coach Ryerson and cupped his face, feeling the stubble under his fingers. "It was so hot being you Coach, I need it again. I need to have a big man bod again. Please coach I'll do anything." Aaron go down on his knees. "I need to suck your dick again too. But as a man this time. I can't go back to being like this and I need that dick."
Coach Ryerson, starting to get hard again, grabbed the boy by the back of his head. "Alright then, get working and when I'm done you'll change."
Aaron quickly got to work taking the member in his mouth, it didn't take long for Coach to come again but this time, was different. Aaron swallowed every last drop fo Coach's cum and then laid down on the floor.
"Coach I-" Aaron stomach was growling. "I don't feel so good."
Coach took Aaron by the hand. "Come on, let's lay down." Coach took the boy to his room and led him to the bed. "Now you're going to be the big spoon alright?"
"But coach-"
"You need to learn how to be a man." Coach got into bed and motioned for where he wanted Aaron to lay.
Aaron did as asked laying in bed, his arms just making it all around Coach's large hairy body. It was nice for Aaron, bare skin up against skin, and soon the stomach ache went away. Soon Aaron felt a warmth in his dick, a warmth he had never felt before. He saw his dick get hard, regrow its foreskin, and slide into Coach's ass.
Aaron tried to pull his dick out but Coach stopped him. "Let me be your cock warmer boy."
Even if Aaron wanted to disobey Coach he couldn't, it felt too good to have his growing cock in the man's ass. As his cock got harder and harder, longer and longer, Aaron felt his body grow. He began to pack on the muscles, his arms and pecs inflating beyond anything he could imagine. He looked like a porn star, too hot to be real.
"Wow!" He said before being scared.
"I like your new voice boy."
"Thanks coach."
"You're becoming a man, address me the proper way."
Aaron understood. "Shut up slut."
That spike of masculinity only made Aaron feel better. He was in a haze of hornyness and masculinity. Before he was a nerd, all he wanted to do was math but now all he wanted to do was eat meat, drink bear, and fuck. He didn't know if this was coach's work or what he really wanted all along. But it didn't matter.
Coach rubbed Aaron's arms. "You're getting hairy daddy."
Aaron looked at his arms, they were getting hairy. Then he pulled away from Coach, just to watch his chest and stomach grow a forest of dark hairs. He felt his face as a long beard sprouted forth and started growing out, farther than Aaron ever would have let it before.
He couldn't help it anymore the changes were making him too horny. He started fucking Coach's ass as his beard and body hair grew, as he got taller, and as his muscles got larger and when he came he felt like a new man.