First, Jeff felt himself growing larger and larger, becoming massively muscled and covered with short, almost coarse hairs. His legs were pushed apart as his thigh muscles became enourmously developed and his arms slowly swung out from his sides, pushed out by his increasingly barrel-like chest and his gigantic biceps. Jim imaginged seeing his frame expand, becoming taller and taller, yet broader at the same time, and he felt as if he could sense his bones and musculature becoming both thicker and denser at the same time. It seemed as if he had easily tripled or quadrupled in weight, yet with his more powerful body, he almost felt light on his feet. Speaking of his feet, Jeff sensed his weight shifting forward onto his toes, which were being covered by thick hooves. The arch of his foot lengthed and shifted upward, moving his legs into a posture more reminscent of a bull's hind legs.
As he continued to grow more and more muscular, Jeff visualized his neck becoming thicker, covered with layers of dense muscle, and imagined his vertebrae shifting into a stable, solid arrangement capable of absorbing tremendous force. Simultaneously, Jeff's eyes almost teared up as he felt his face lenghtening and his nose and mouth shifting forward into a snout. He felt an increasing weight as a mass of bone and horn grew on his head, forming itself into two broad, stout, curving horns. The added weight was unusual and Jeff shook his head and was startled to feel his ears, now furry, flick themselves with new muscles and brush against the bottom of his horns. The tingling sensation seemed to fade, leaving Jim with a feeling of unbelievable power and virility.
In fact, the sensation didn't fade as much as concentrate into the center of his being and then shift downward, sliding enticingly toward his groin. Jeff felt butterlies in his stomach(s?) as he anticipated the changes to come.
Jeff felt a warm, heavy weight descend into his testicles as his sac began to expand outward and down, sliding across the hairs on his gigantic legs. His balls swelled and swelled, becoming fuller and fuller with what must be an enourmous, almost endless supply of semen. Despite even the colossal muscles of his legs and back, Jeff's center of balance shifted forward to his groin as his balls grew even larger and heavier. As his scrotum slid past the mid-point of his muscle- bound thighs on its journey towards an even more stupendous side, Jeff thought to himself: "With balls this huge, I'll be able to cum for hours...I can fuck dozens of women...hundreds of times." Finally, his now gigantic balls stopped their growth, resting heavily on his legs from his crotch to just above Jeff's knees, spreading so broadly that the sides of his scrotum were almost even with the outer curve of his legs, despite his huge thighs and broad, spread-legged stance.
Now Jeff felt the tingling focus in on the root of his already rock-hard penis and he almost came just in anticipation. His cock became semi-flaccid as it grew longer and thicker even faster than blood could be pumped in to fill its swelling form. Jeff could imagine his penis, growing longer and thicker by the second, stretching larger and larger as its now enormous head reached, then passed his knees. The warm, meaty weight of his expanding cock was so tantalizing that Jeff had to restrain himself from gripping it firmly in one huge, muscular hand. "Patience," he thought, "soon I'll need two hands to encompass my dick." Rather than sliding down between the crevasse between his elephantine testicles, his penis had slid over the curve of his right ball and past his knee and was now growing steadily down his right leg. The gentle friction of his leg hair (fur now) made his cock twitch with delight and Jeff shuddered deeply with pleasure. Earlier, his collosal balls had made his erect penis seem almost comically small, but the unbelievably thick, ruddy cock that now grew past his ankle made his testicles nearly look small in proportion. Jim felt a slight pang of regret as his now gargantuan cock stopped its growth, brushing the ball of his big toe (hoof?) as it swayed in rhythm with Jeff's lust-filled panting.
Jeff opened his eyes and gazed with unsurpassed pleasure at his new form. His giant frame, nearly eight feet tall, was incredibly, almost impossibly muscled, and covered in thin, reddish brown hair. Despite the enormous expanse of his chest, Jeff could look down and see the curve of his titanic balls and the unreal size of his cock. At the sight of his own cock, Jeff became even more aroused and almost fainted in disbelief as his turgid penis became to swell and swell with blood. Already at a mind-boggling size, his dick thickened and lengthened more and more as it became erect. Veins the size of a normal man's thumb popped out on the reddening suface of his cock as it slowly swiveled upwards, first to 45 degrees, then 60, then 90, then even higher. Jeff lovingly rubbed the base of his monster as it continued to swell and swell. Finally, having swollen to twice the length and almost thrice the circumference of its flaccid state, his cock stopped growing, its massively huge purple head now at Jeff's eye level, although so far out from his body as to be unreachable, even by his gigantic arms. Totally engorged, throbbing with heart-stopping pleasure at even the slightest breeze or movement, Jeff's now ridiculously over-developed cock monopolized his attention. Jeff thought: