Mark's heightened sense of smell could tell when the change took effect. He was mostly immune to his own scent but still he could smell the way the rich, heavy scent thickened until it saturated the entire room. He gave a slight purr knowing that anyone who entered the house would smell it anywhere they went. He could only imagine how it would effect other people.
He turned back to the Chronivac, bringing up the draft of Jeff from before. His massive cock re-hardened at the sight of the computer model and Mike wasted no time hitting "APPLY", after which he stood and walked over to the bed, eyes fixed hungrily on his son.
Jeff was stretched out on his stomach, limbs sprawled widely, giving Mike a wonderful view of his pert round ass, coated with a thin layer of fine blond hair, his tail lolling to the side and twitching lightly in his sleep.
The transformation was timed to take ten minutes, giving Mike enough time to truly appreciate how Jeff would change. He wanted to be able to treasure this. Maybe in the future he would put Jeff through some more changes just to watch them...
Suddenly his heightened senses picked up on movement, and his attention returned to his son.
Jeff's legs had begun to lengthen very, very slowly, his feet growing as well. The blond fur covering his legs was thickening from the thin, almsot invisible fluff it had been before, becoming scraggly and thick. The thickening hair raced over his feet and up his calves and thighs before reaching his ass. Fur flooded over the round globes, growing even longer in his crack. The hair on his tail thickening before continuing its path up his back, layering the hair already there.
Mike was about to turn Jeff over so he could see his front, but, as if he could read his father's mind, Jeff moaned in sleep and rolled over, giving Mike a full view of his front. He would guess that Jeff was around age 15 now and the growth was really starting.
Jeff had grown a lot hairier. Before he had fur, but not very thick, nothing like his father's--the same way a human boy would lack any real growth. But now the fur by his crotch had thickened heavily, curling more than a lion's would. The thickening hair had moved past his waistline and was travelling up his chest, spreading across his still-flat chest though leaving the nipples uncovered. His cock was visibly swelling both from arousal and the transformation, growing very quickly. The previously small testicles were bloating and fattening, filling with life-giving semen.
Before long Jeff hit the growth spurt Mike had been waiting for. Arms and legs swelled with length and muscle, furry paws doubling in size. His pecs ballooned out, shoulders growing as his biceps and triceps quadrupled until they passed that of a linebacker. His face grew harsher, canines long enough to extend past the lip of his maw, mane filling out around his face and giving him what humans would call a full beard.
Mike growled in his chest, fighting the urge to cum right then and there as Jeff's cock and balls swelled so large they would likely make him walk bowlegged. His balls were massive and hairy, his cock thicker and longer than a man's forearm and oozing clear pre-cum.
Finally the transformation ended, leaving Jeff exactly how Mike had wanted. Huge, beefy, hairy and hung, his grown man-cub.
Now what to do...