"Oh yeah." Repeated Ty. He closed the remaining distance between him and Gavin, bringing their faces to an intimate distance. "How would you like to be a little more muscular?" he asked quietly.
Gavin, curious at the close face of the happy, soft-faced boy, gulped, "yeah."
"Then kiss me." Ty made the decision for him, bringing their lips together.
Immediately, Gavin felt a buzzing in all his muscles. He assumed it was the excitement of the kiss, and ignored it as he kissed back. If this was going to make him more muscular, why not?
Ty brought his hands up to the sides of Gavin's pecs, then around his wide, warm back. As they deepened the kiss into a wet, exciting episode, they both felt Gavin's back widening slowly as his lats grew. Ty could feel Gavin's pecs, which had already been somewhat impressive, begin to swell and push into Ty's chest, without regard for Ty's presence there. Gavin felt his biceps hardening, his butt swelling, even like he was becoming a little bit taller, when Ty broke the kiss. Everything stopped.
Gavin opened his eyes and and refocused on the face in front of him, each of them wet from each other's mouth. Ty began to sink down, dropping a kiss or two on each pec, then on his faint abs.
"Wooow..." Gavin breathed, flexing out his enlarged triceps, bursting into large horseshoes, feeling the kisses of Ty step down his pumped up torso. He would surely be the biggest of all his classmates now.
Ty sank to his knees and pulled down the pants Gavin had only recently put on. He thought he had felt the bulge, and he did see it through the underwear he was now removing, a less than 6 inch erection. He looked up at Gavin, and Gavin couldn't believe his luck as the same cute face he had just been kissing took his cock into its mouth.
Like the expert Ty had made himself, he used the first few strokes to lube it up. He broke eye contact when he closed his eyes and focused on his task, putting one hand on Gavin's big, globular buttock and another on his padded abs. He quickly took the whole thing in, beginning to suck in earnest, and timing his work with his sucks.
Gavin could feel a tug at his cock, like this expert little cocksucker was pulling it out, but he also felt something else. He felt a relief, a pleasant shifting in his body that was moving from everywhere to his crotch, and up his cock. With each lick up, his pecs seemed tighter, harder, and more defined. Ty was taking the fat off him.
Ty enjoyed sucking Gavin's dick as he lifted more and more fat off of Gavin's body. Without even opening his eyes, he could see it in his mind's eye, and feel it in his hands. The buttock in his hand eventually became rigid and sharp. Ty relished in the way Gavin's abs undulated with his ministrations, surges of pleasure Ty was causing with his mouth meeting with more and more shredded abs each time.
The fat melted off of Gavin, taking him from beefy to outright jacked. His pecs showed their fibers, his delts proudly popped with three distinct heads, his lats and traps encroached on his figure from behind. His abdominals ferociously celebrated their appearance, flexing and heaving with deeper and deeper ridges of a 6 pack, then an 8 pack, threatening to burst with a 10 pack leading right down to his crotch. His swollen biceps jumped with the power of two distinct heads, and he couldn't help but pop his pecs into little boulders as he grabbed the back of Ty's head.
By the time he was ready to cum, Ty could even feel striations in Gavin's ass. Ty caressed the powerful muscle one last time before grabbing both of Gavin's shredded, powerful quads in preparation for Gavin's orgasm. Ty sped up and looked up, so he could admire nearly every muscle in Gavin's body flex as he came with an immense orgasm into Ty's mouth.
Ty breathed deeply as he wiped the mess around his mouth. Gavin breathed shallow breaths as he reeled from his orgasm.
When he recomposed himself, he looked at his body, flexing it again to feel the novelty and power. "I'm incredible! I'm so shredded! Look at these abs! Thank you, Ty! I feel SO strong! I'm the hottest guy in the grade! Woah, even my cock is bigger!"
Ty admired his work, especially the job he had done with the now 8 inch cock. "Look at you. You're a demigod! All because you kissed a god," he giggled.