John stood back up from the wooden bench, still furiously jerking off his cock as he admired Coach's nude body in front of him. Coach's own massive boner was still rock hard, despite emptying his load into John's mouth mere moments ago. Ryerson slowly stroked his 11 inch cock as he watched his student jerk off.
As John continued to masturbate, he felt a pleasurable tingling sensation enter his cock. The euphoric feeling quickly spread until John's entire body felt electric. Slowly, John's 7 inch cock started to shrink down and grow thinner in his grasp. John looked down in a panic and watched as his dick dwindled away in his hands and regrew its foreskin, settling in at a new length of 6 inches. John noted that his new cock looked identical to that of his boyfriend Aaron's.
"What the hell?" John exclaimed. He wanted to stop jerking off, but the feeling was too good and he couldn't control his urges. John felt his balls shrivel up and contract as his pubic hair changed from dark brown to light blonde before receding into his crotch, leaving his dick and balls completely smooth.
John grew shorter, shrinking from a height of 5'7 to 5'3. His muscles started to melt away, his shoulders losing their broad definition and taking on a much more slender frame. His biceps wilted away as his arms grew scrawnier. John watched in horror as his impressive pectorals shrunk down and his washboard abs melted away to a smooth stomach, leaving him a with a lithe frame featuring little definition. John's legs slimmed down to a fraction of their original size, looking like twigs in comparison to the massive tree trunk thighs he had had before. Even John's tight firm ass lost its definition, rounding out as it packed on some additional cushioning.
John couldn't believe his eyes; he had lost his perfect runner's body in a matter of seconds! The pleasure originating from John's cock increased tenfold, and he knew he must be close to cumming. John increased the pace at which he was masturbating, unable to stop despite his internal protests. His styled wavy black hair grew longer and messier, brightening to a light blonde. His face shifted into Aaron's; his sky blue eyes shifted to a dark brown while his sharp nose rounded out and his thin lips grew fuller. With a large grunt, John's cock started to spurt cum, spraying Coach Ryerson's chest with his seed.
Coach Ryerson wiped the cum off his chest and licked it seductively, grinning at his student. That his cum had caused John to turn into Aaron was an unexpected side effect, but not an unpleasant one.
Aaron looked around the locker room in confusion, trying to get a bearing on his new surroundings. He looked down to see himself in nothing but a pair of ill fitting boxer briefs with his cock out, then noticed that Coach Ryerson was standing in front of him, naked and horny.
"Welcome to the party, Aaron," Coach grinned, sliding his hand along his shaft.