After finishing their current round of shared pleasure, Ty and Ky lay on the bed, panting and smiling. They stared up at the white void for a few seconds, then turned their heads to each other. They were glad to be conjoined, to be full-blood brothers, to have a big void of their own in which they could do whatever they wanted. After a few seconds, they got up and pulled their clothes on. They stared at the free-standing door, and began to wonder what the conjoined Dustin and Justin were doing in their void. It was already great sharing a body with one other person; it was also great to think that there were two such bodies in their void.
Then Ty began to think of something, and it wasn't long before Ky noticed him thinking deeply. It was something that both Ty and Ky could experience, with or without the others. It was the kind of thought that made a person like them smile, for one reason or another.
"What are you thinking of?" Ky asked.
Ty turned his head towards Ky, leaned towards him, and whispered the thought into his ear. Ky listened carefully, and soon began to smile in agreement.
"So you want to do it?" Ty asked.
"Why not?" Ky answered. "We have the time, the space, and the ability."
"Okay. Give me a second," said Ty.
Ty relaxed, and then focused on their next transformation. First, he made everything in the void disappear, except the floor and the door. Even the bed disappeared, but they would bring it back soon. Then their body began to change, which was exactly what the pair were waiting for. They braced their arms with their hands on their hips—their widening hips. Their heads and legs stayed in place, while their hips and shoulders grew even wider and stretched out, with their shirt and jeans doing the same. When there was a good amount of space between a head and a shoulder, a hole would appear in the shirt, and a lump would grow out and form into a new, identical head. At the same time, the jeans would grow a new leg, and a lump would form into a new leg, while something else grew next to it.
This process continued for about thirty seconds. A new pair of heads kept growing, along with a new pair of legs. The shoulders, torso, and waist kept growing wider with each new appendage. When the transformation finished, Ty and Ky stood proud and straight as they and their new body bros greeted one another. Altogether, the body now had sixteen identical heads, with those of Ty and Ky in the middle. They were standing on sixteen legs, with only two shared arms (which could be added to, if necessary).