Mitchell stared at his hooves and equine sexual equipment, then back at Jacob. "If I become a horse, then I won't live as long, will I?"
Jacob thought about that. "No, you'll be old when you are 25, not just starting life on your own. But I'll make sure you are healthy and happy."
"Then I want to be an unborn foal." Mitchell sighed. At least that way I get to grow up as a horse, and I'll have the most life."
"That is probably a good choice," said Jacob as he moved close to the boy. "Of course, you'll be a new creature, and have no memory of ever being human at all." His enormous cock hardened again and he touched the tip to the dark falre on Mitchell's equine penis. There was a surge of pleasure and warmth, and Mitchell gasped and tried to pull away. But the two horse-men were now joined by a single, long black shaft.
"What's happening!?" Mitchell felt himself being drawn closer to Jacob, and realized that the man he thought was Mr. Perth was also getting taller. No, Mitchell was getting smaller! He looked down at himself - his body was getting thinner, smaller, younger. Fifteen, then thirteen. Intense sexual pleasure came from the shared penis as semen pumped through it in huge spurts. Mr. Perth's already large horse testicles were swelling with each pulse, now the size of grapefruit!
"You want to be an unborn foal - so I am going to make you mine." Jacob smiled, enjoying the pressure and pleasure of his stretching balls. The boy was already shrinking past puberty, no more than ten years old and dropping years fast.
Mitchell looked scared now. "It's happening so fast! Please, I don't want to go away!" He was maybe six years old, and the immense stallion's shaft actually lifted him off the ground. He flailed his arms and legs helplessly as he dwindled to age four, age three. His blue eyes turned cloudy as he turned into an infant, and his body flopped as the bones and organs all turned to thick semen. Then, with a final pulse, the last of Mitchell was sucked into Jacob's straining balls.
"Uhhhhnnnnn." Jacob staggered towards the young filley that had been the real Mr. Perth. She was hot and ready, and would make a fine mother to the new foal. The immense load of semen that was Mitchell wanted back out now, and it took all of Jacob's willpower to keep from spewing like a firehose. His testicles were almost touching the ground, now the size of basketballs. Every step sent a wave of pleasure that screamed for him to let go.