For the first minute, nothing happened. Your expectation dropped as you thought that his experiment would work. This is the first time he was so confident about his invention.
"Aw damnit! I thought it would wor……" His voice was cut off as he suddenly shuddered more violently; he gasped from apparent pain.
"Oh my god! Are you okay?" You shouted, grabbing Kyron's shoulder, trying to comfort him, panic starts to flood your mind.
"I'm fine. Just the potion's side effect" He is still shaking horribly grit his teeth from the pain and strong burning feeling that was coursing through him. Inside Kyron's body, his bones reshaping and lengthening making him taller. You watched your mouth agape, as Kyron's muscles, all of them tensed, bulging outward as if he was flexing them all at once. Then his muscles grew.
His chest was the first to grow. You watched as his flat chest inflated to a set of admirable pecs bulging and straining against the white T- shirt. His nipples poked against his shirt, no doubt getting rubbed by the material as they swelled. Then your cock twitched appreciatively as his favorite muscle part started to shift and stir. His biceps and triceps inflated into small balls of muscle threatening to rip his shirt. When his bicep seemed to have reached its peak, the growth wave washed along his forearms. One second he still had his slim forearms, the next they bulged out at the crook of his arm, lines of definition appearing as the muscles rose up like stone, veins snaking along them too to pulse against his skin.
You were drooling slightly as Kyron who was once a "runt" to his species is becoming more muscular by the second. You look down and see his quads grows proportionately with the rest of his body, his calves grows into a perfect diamond shape. His legs started to bulge against each other as their increasing size reduced the space between them.
After a few minutes of continued rapid growth, it slowed down as you heard this sound.
"SHHRRIIIIIIIIIIIIIIIIIPPPPPPPPPPPPPP……." The sound echoes throughout the room as you see what it causing it. His shirt rips off in the middle and his biceps grows out of the shirt getting bigger than ever destroying the sleeve. Your cock twitched, become as hard as steel and dripping with precum. His pants can't contain his enormous quads and rips open everywhere revealing the growing python in his underwear. That once tiny penis has definitely become bigger, maybe 50% longer and thicker.
Finally the growth stops. You examined him again to see the result.
The potion had left him with some rather solid looking shoulders, ones that were nice and wide, with the remains of his poor shirt hanging on it. In the middle section, there is a faint set of abs forming. His horns has grown bigger and longer
He isn't huge but his muscle is defined like he was going to the gym everyday. You estimated that he had probably gained at least 70 lbs of muscle and 7 inches in height which puts him at about 6 feet with 210 lbs of solid blue dragon muscle. You look down to see the remaining fabric of Kyron's underwear barely covered the huge piece of blue meat that is about 8'' and as thick as a beer can. And he isn't hard yet. Not to mention the 2 huge and plump balls as big as tennis balls that is practically churning with cum. You can't even imagine how muscle can those orbs produce.
"Shit, I should have taken off my clothes first before drinking it." He said with a deep baritone, making you leaking cum like a broken faucet. Then Kyron looked at me with a naughty grin on his face. You try to say something but no words came out.
"Fuck it!" He ripped the underwear off and the rest of the "rags" on him. Then he hits the most muscular pose. His body is covered in veins, every muscle in his body is bulging with power. His draconic cock is now rock hard at 10'' and as thick as a wine bottle, already dripping a puddle of cum.
"Do you like it?" Kyron said with the deepest and sexiest voice, flashing the most cocky grin on his face. After you heard that, you let out a moan and cummed so hard with the biggest load of your entire life that you fainted.