As soon as Jeff pressed the button, the changes started.
Jeff’s body felt as if it were on fire. He stripped off all his clothes. His penis stood at full attention. Hard, swollen, and engorged.
Jeff’s toenails started to darken in color. His toes merged together too. His feet were turning to in to hooves. Jeff was forced to stand on the front of his feet as his feet stretched. Jeff looked down at his newly formed hooves.
Jeff’s penis began to deform next. His erect cock began to stretch outwards and get thicker. It kept growing and growing until it was nearly two feet long and thick as a soda bottle. The color shifted from a pink fleshy color to a dark velvety black. The mushroom head of his dick flattened. Jeff’s new horsecock was stuck up against his chest. Jeff was completely awestruck and dumbfounded at his brand new equine member.
Jeff’s balls grew too. His testicles swelled up to the size of oranges and turned leathery. The weight of his new testicles caused them to hang lower.
Jeff’s ass started to change next. His butt quickly grew and grew giving him a huge round ass. A silky horse tail snaked its way out from the cleft of his ass. Jeff’s ass cheeks parted revealing his anus, which moved to sit under his tail. It began to turn black and leathery and enlarged. Jeff had a perfect equine asshole.
Near his hips, two horse legs stretched out. Jeff’s torso snapped backwards as his lower horse body finished up.
Jeff was now completely a centaur. His human body was still that of a unmuscular pubescent boy.
Hair began to grow over Jeff’s face. Jeff now a full bushy beard. His pectoral muscles swelled up, as did his shoulders and biceps. His nipples expanded from the size of dimes to the size of silver dollars. His very light two pack abs hardened in to a hairy eight pack. His human skin turned tanned almost golden. He was the very definition of a centaur. Sexy, masculine, full of muscles with a huge horse cock.
Jeff looked around. He was no longer in his room, but was in a horse stable. Below him was a hay lined floor. To his right was a horse and to his left was another horse. All around him were horses, but no centaurs. The smell of horse manure and horse piss oddly enticed him.
“I could get used to this” Jeff said to himself as he rubbed his hands over his body.