Jeff's Chronivac programming included a transformation for himself, triggered after he had fucked both of Jenny's pussies. He felt a tingle in his dick, and looked down to watch, as his dick started growing. He was was of average size before, but in just a few minutes his dick grew to over two feet long, and doubled in girth. His balls got much larger as well. It was amazing to see, and Jeff couldn't help grabbing his monster member with both hands and running them up and down the length of it. It felt so great that he nearly forgot Jenny's presence and his plan, but he reluctantly stopped because he didn't want to deprive Jenny of the fun. "Let's see if this actually works," he said, as he thought about the details of Jenny's transformation.
He started shoving his fat dick into Jenny's upper vagina. It was a fairly tight fit, so he had to take it slow. After the first six inches were in her he nearly blew a load, but he kept going. Jenny's vagina seemed to tighten further in, and he could feel her muscles contract, but he kept pushing. Twelve inches, eighteen inches, if he thought penetrating her felt great before, it was nothing compared to this. This position, entering her upper pussy, was interesting because her huge breasts were so close at hand. He squeezed them as he continued to push into her. When he pushed another six inches, he could feel his cock head poke out of Jenny's lower vagina.
Jeff lay down on top of Jenny's torso and touched the head of his dick. "This is so amazing," he said. He was able to push just a little more into Jenny, and another few inches of his penis came out her lower vagina. "I wonder," he thought, and licked the head of his penis. He tried sucking the head, and because of his increased girth, could only just barely get it into his mouth. He was penetrating both Jenny and himself! He let his cock head back out of his mouth, and said, "Well, I can try more of that later." He got to work thrusting back and forth through the length of Jenny's single, long vagina.
He could feel Jenny clenching the entire length of her vagina around his very long penis, and it felt incredible. He continued thrusting slowly, but gradually increasing in speed. Sometimes he thrust far enough for his cock head to pop out of Jenny's lower pussy, but other times he kept it in. It felt great either way. Before long he felt an absolutely mind-blowing orgasm, and shot thick ropes of cum through his long dick, and all the way out of Jenny's other pussy!