As pleasurable as it seemed now, Derrick did not want to spend the whole two weeks of his vacation being the personal slave to a centaur. And he had a bigger concern that the job was not just for two weeks. Mustering up all the willpower he could manage, Derrick stepped back and away from the centaur. "I... I not... am not.." He had to struggle for the words and was afraid it might already be too late. The reflection showed him to be almost fully changed into one of the horse-boys, though his skull was not quite so flat, and his features were still vaguely recognizable. Still, his mind was clearing now that the centaur's hand was not reshaping his skull. "I do...not.. want... to... stay.. here."
There was disappointment in the centaur's eyes, but he smiled and nodded. "There is time yet. You accepted the change - I could not have made it otherwise. If you change your mind, you are welcome back any time. You will always know the way to my stall."
God, the centaur was beautiful and amazing and Derrick felt a powerful urge to surrender to him now, but resisted with great effort. As he did, the horse-boy in the mirror shifted and became more human. Derrick's mind cleared more, and he moved fully out of the stall. Some of the changes had reversed, but when he looked down at himself he was still far more like the stableboys than his old human self. That included the massive, dark sexual equipment - somewhere along the way he had lost his clothing - and the odd, three-fingered hands. He walked on hooves now, and the odd elongation of his arms and legs made him better suited to caring for the massive centaurs. He also understood without being told that he was somewhere near the dividing line between beast and human, though he was not sure which side he was on. The oddest thing was that while Derrick knew he was no longer human, that back home he would be considered a bestial freak, he felt perfectly normal. Well, not quite - when he looked at the other stable boys, they were the 'normal' ones.
With great effort, he turned and trudged back to the guest areas. No one stopped him, and though some of the guests stared, most seemed to accept the odd horse-boy as just another odd creature.