Chris shooed Matt off the computer, not caring he was sitting down in his roommate's chair pantsless. He was enjoying the feeling of his pendulous cock swinging between his legs.
"What are you going to do?" Matt asked dubiously, but Chris only grinned as he brought up Matt's stats, poking around the program a bit to see what he could do.
"Damn dude, you're two inches taller than me but weigh five pounds less?" Chris said as he looked over Matt's stats. Matt was still short at 5'6", but he was a scrawny 115 pounds.
Matt just shrugged as he sat on the edge of his bed, eyeing the mess on the wall they had made, thinking they'd need to clean it up. Really, he was trying to distract himself from what his roommate was doing, he figured after the horse cock thing he owed him one. Was it his imagination or did he feel a tingle running through his body? He looked over to where Chris was sitting, only to see his roommate sitting there with a cocky grin on his face watching him.
God, he must be nervous, he felt hot, and his shirt felt way to tight. He looked down. No, it didn't just feel too tight, it was too tight. It was hugging him in a way no shirt ever had before. Sure it was a small size, but even that usually hung on him a little. Then came the sound of a seam popping, and he looked over to see his shirt sleeve had split open around his arm. An arm that didn't look like a stick, there was.. meat on it. The shirt felt like it was choking him. He reached up to the collar and yanked, the garment tearing open on an already weakened shoulder seam.
He could breathe again at least, though his shirt hung from his left shoulder, leaving his right shoulder and arm exposed. He was seeing curves and grooves he had never seen before on his body, he could make out the muscles of his upper arm, and his chest seemed to swell. With another tug he pulled he ripped the shirt free of himself, the weakened fabric coming apart with little effort. His hand went right back to his chest, feeling the two developing mounds of muscle, firm but pliable. Not like the flat, bony chest he was used to. He could see the muscles shifting in his arm as he moved them about, it was fascinating. "Holy crap."
Chris grinned as he watched his roommate fondle his growing muscles. "Oh, just wait, you're going to love this.."
"What.. how much..?" Matt was at a loss for words, especially as he had to get up and shuck his shorts. The waistband wasn't the problem, his thickening thighs were straining the fabric, and it wasn't as thin as his t-shirt. Even his underwear gave way after muscle swelled in his rear, the elastic snapping before they fell to the floor, leaving Matt standing naked, staring down at himself. He was still mostly hairless, except for a patch around his cock, which was standing at 5-1/2" inches, completely erect.
Chris felt the old pang of jealousy rear up as he noticed Matt's cock. It was average, but when you were small, average was something to be jealous of, until he remembered his new size, grabbing his cock to remind himself of it. Then he found himself stroking it as he watched his roommate grow. He was getting turned on by watching a guy swell with muscle? He knew that wasn't like him, but he found himself not caring. "Oh... I just had it add something like 60 pounds to you, mostly muscle..."
"60?!" Matt practically squeaked. He didn't know how much he had already gained, but his stomach was forming into a nice four pack as he thought about it. He actually felt unbalanced for a moment and fell back on the bed as his thighs swelled more, pushing his legs apart. His pectorals were going from flat plates of muscle to slightly rounded mounds, and some veins appeared snaking down his arms as his biceps and triceps continued to pump ever larger.
Matt had never felt so amazing in his life. He lost himself in the feeling of power his growing musculature was giving him. His hand squeezed his pectoral, then caressed it until he found his nipple, twisting and teasing it as his four pack hardened into a six pack into an eight pack. He could see definition on muscles he didn't even know he had. The heat seemed to be fading as he felt a few last electric jolts pass through him, the last one causing his cock to twitch and shoot a load across the room to splatter on Chris' already cum soaked bed. He hadn't even touched his cock..
"A little more hair on you and you'd pass as one of the school jocks." Chris joked from where he sat, still subconsciously running his hand over his cock as he looked at the musclebound Matt.
"I pass even without the hair, fuck.. Maybe I should join the wrestling team." He meant it as a joke, but the thought of wrestling a few of his more muscled classmates got his cock swelling again. Then Matt heard the sound of someone typing away on a keyboard and looked over to see Chris working away. "Hey! It's my turn.."
"Too late!" Chris said as he dramatically his the enter button.
Matt felt the tingle come over him again..