As Mike drifted back off to sleep, Brian busied himself with the centaur's lower body. More rubbing and brushing did almost nothing, though, as Mike's horse parts were pretty much totally Shire stallion and perfect. It was a little frustrating for Brian to have the human parts still needing to be changed. He finally got up and moved over to the small pond near the campsite, afraid that he would drift back into grooming Mike into a horse.
He frowned at his reflection in the pond. It wasn't so bad being human instead of an elf, but he did not like being so young. If he was maybe 15 or 16, but looking like a ten year-old sucked. And a pretty ten year-old - he could be a girl if his hair was longer. Working on Mike was fun, and the idea of being a stableboy forever did not bother him at all. He sighed splashed at the water to disrupt the reflection. When the water stilled again, he frowned at the boy reflected back. Weird. He looked older, darker, maybe 12. Surprised, he felt his face but could not tell much. It wasn't until strange sensations drew his attention lower that it became obvious he was maturing.
What had previously been a pre-pubescent nub was blossoming into a very respectable uncut cock. He felt it as he looked back in the pond to see a coarse-featured 14 year old with buck teeth and big ears. No longer pretty, for sure. But Brian liked this new face. And the body! He was still lean, but instead of a skinny boy, he was well-muscled, wiry.
The changes slowed, and finally stopped after several more minutes. Brian gaped at his reflection, now that of a homely, but very well endowed and trim 16 year-old. From the matted brown hair and filth over his entire body, he had no doubt he was a stableboy, and had been for many years. He grinned and looked over at the still-sleeping centaur. For a moment, he felt a flicker of regret or guilt about what he was going to do. Then he dismissed the strange thoughts as he got up and moved quietly back to Mike. The centaur was already partly changed, and it would be easy to finish him up while he slept. The centaur would drift from the mentality of a human to that of a horse in his dreams, and wake with the thoughts of the beast he should be.