Deciding, Jeff clicked on the 'Age' tab. He thought for a moment about how old he wanted to be. While the idea of making himself 10 was appealing, to try being a kid with his new father, he was more eager to see what he'd look like as he got older. So, after a moment of deliberation, he entered '26' and clicked 'TRANSFORM'. He figured that 26 was old enough to be done growing, but young enough to still feel like himself.
A rotating hourglass appeared on the screen, a progress bar beneath it, color sliding slowly across it. Jeff stood up and moved in front of his full-length mirror, staring at his beefier form for a moment before peeling off his shirt and tossing it onto his bed. He eyes his new form appreciatively as the changes began.
The first thing to change was his height, his legs and torso extending so fast he nearly fell over. He shot up several inches, finally stopping at just under six and a half feet--much taller than he'd ever been before. Next his shoulders broadened, filling out his form with muscle. His waist and hips stayed slim, giving him a sharp V-shaped torso. The muscles began to swell, growing from toned and defined, to actually large. His pecs filled out into a cut shelf, his abs pressing further from his stomach and becoming sharp ridges in his torso. His arms packed on meat quickly, biceps and triceps doubling. His forearms grew larger, hands becoming like catcher's mitts, rough and strong.
Next his face began to alter, his square jaw expanding a bit more, chin and jawline becoming sharply defined. His hair shrank back into his skull slightly, leaving his face uncovered in a more adult haircut. His nose lost a bit of its pertness, and his brow seemed to increase a bit, giving him a sharply-defined face. His throat tickled as his adam's apple grew, and he remembered how deep his new father's voice was.
Much like before, the last thing to come was the hair. As he'd expected, he would grow up to be a substantially hairy man. It started with an itch, and Jeff quickly kicked off his shorts and underwear to watch. The hair on his crotch thickened first, spreading down his thighs and increasing his already thick leg hair until it covered most of the skin, spreading across the top of his feet and toes. Next it moved upward, the trail at his navel thickening into a highway of hair, spreading to cover his entire abs in thick dark curls. The path between his nipples grew outward, connecting to the circles of hair and filling out across his new pecs. It stretched from armpit to armpit, funneling down slightly at the shelf of chest muscle to meet with the hair on his abs, making almost his entire chest covered. It swept up to his collarbone, a thin layer fading over his shoulders, and the last bit moving up to his jaw, where the thin wispy stubble he'd had filled out to a thick dark 5 o'clock shadow and then into a short beard, reaching up to his cheekbones.
Jeff ran a hand down his torso, the thick dark hair catching in his fingers as he felt the hard curves of muscle. His dick was painfully hard, oozing a thick stream of pre-cum down to the hair bush covering his crotch. He felt upwards, the chest hair turning seamlessly into the scruffy beard adorning his face. All the hair on his body was interconnected.
He flexed, watching his muscles bulge obscenely, so large they could be deemed bodybuilder-large. The thick hair just heightened the sharp ridges, making him look even more virile and masculine than he'd imagined possible.
Jeff grabbed his cock with one hand, marveling at the sensations of his calloused palm on the sensitive skin. With the other hand he tugged on his chest hair, ran his hand over his beard, and let it slide down to feel his newly fuzzy ass cheeks. He hesitated for a fraction of a second before he began to gently probe his hole, loving the feel of the warm, tight globes pressing on either side. He circled it for a moment before pushing his finger against it, the tip sliding inside.
At that he lost it, groaning deeply as he came, his semen shooting up to splatter all across his image in the mirror. It seemed to last hours before he came down--his cock remained hard, and he was tempted to have another go before deciding against it. He watched his cum ooze down the mirror, his reflection breathing heavily as he did the same.
Jeff returned to his chair with a sigh, loving the ever-present scratchy feeling his hair gave. His cock was still semi-hard, oozing slowly, but he ignored it as he noticed the new box that had popped up.
ALTER WORLD TO FIT?
Beneath it were two boxes. The first said 'CHANGE NON-USER MEMORIES?' and the other 'ALTER WORLD COMPLETELY TO FIT?'.
Jeff thought for a moment before deciding...