John was reverting back to his being a teenager youth when his imagination got the better of him and he forgetting of what was hung about his neck, did speak his fun fantasy as if it were a real wish.
The Medallion did as its creator had preset the magical artifact to do, as of granting any sort of sexual wish to anyone foolish enough to be warring the Medallion, and speak aloud their lustier ideas. As then what was like that of a stallion horse replacing everything south of the belly button on John to being akin to a mature stallion horse, did become again like it was just moments previous.
With a wanted and wished beastly sense of sexual lust driving John onward, as he entered another horse stall and stood chest to a rounded furred rump, he failed to take note that his torso was growing longer, larger, more like that of an equine.
John made good use of his left arm and hand to position his erect horse cock for perfect entry into the winking vulva lips there before him. It was then as the bloated flat cock head was pushed snug to the vulva lips, that he in his mind did hear a small voice expressing of thanks for the reprieve from being the anus of an old horse.
The voice tended to break the moment of sexual concentrating upon his having sex, as mating with a horny mare.
"Huh, what am I hearing Medallion, who else is inside my head?" John said, as not expecting the silver artifact hung about his neck to offer an answer.