Jeff could scarcely believe how his afternoon had gone.
Just 20 minutes ago he had been a young virgin man. Now, not only had he put his dick inside his girlfriend, he WAS the dick. An enormous, 6 foot tall penis that was somehow thrusting rapidly in and out of the bed-sized pussy his girlfriend had become.
Why Jenny would want to be a living vagina, Jeff had no idea. But he wasn't about to complain. The feeling of Jenny's slick muscles squeezing his shaft and head was more than enough to convince him this had been a great idea. Despite having never been a man-sized-cock before, Jeff did know what an orgasm felt like and he could tell he was close. His cock-body stiffened which felt like he was stretching after a nap. He was very aware of his balls tightening up in preparation for their important act. He was about to cum in a pussy for the first time ever and he was going to get a front row seat to watch!
Jenny, meanwhile, was having far less coherent thoughts. Being stretched wide open by the largest cock in the world had made her mind fuzzy. And unlike Jeff, her view was the uninteresting ceiling. She had zoned out somewhere around the third orgasm. After that they had begun to blend into one another and she'd lost track of them long, long ago. All she knew was that she was practically split in two and it was making her gush liquid onto the mattress beneath them. Beyond that, all she could comprehend was intense pleasure.
But now her attention focused on something new. The enormous balls that had been slapping her underside suddenly weren't slapping quite as hard anymore. Jenny managed to bend her clit downwards, like a chin nodding, and she could actually see Jeff as he pulled in and out of her; his huge, slick body turning her on even more as she looked at it.
But there was something else... Even as sexually inexperienced as she was, she knew what she felt. Jeff's balls were tightening up! He was about to cum! Sure enough, now that she was paying attention, she could tell that Jeff had stretched out and gotten even harder. Her boyfriend was about to fill her to the brim and she could not wait! Her labia vibrated in anticipation as she squeezed him the tightest hug she could muster.
Just then Jeff slammed deeply into Jenny and held tight. His balls trembled, his shaft shook, and his head twitched once, twice, and then opened up and unleashed its warm contents all over Jenny's cervix. She felt Jeff trembling and the knowledge that she'd given him an orgasm made her cum all over again. The two gigantic genitals shook and thrashed on the bed as they mated. Jeff could barely think straight as Jenny idly thought about how she couldn't get pregnant since she had no womb.
They froze for a moment, seemingly catching their breath even though neither of them currently had to breathe. And then, Jeff felt himself get... softer. He went from 6 feet tall to 5, and then 4. At this point he felt himself sliding out of Jenny's tunnel as if it were a water slide. He popped out and fell on the bed, looking up at a 5 foot tall vulva, at this point nearly twice his size as he slid backward towards 3 feet and then 2.
I guess he's a grower, not a shower, though Jenny, laughing to herself. She suddenly felt proud and powerful, being so much bigger than her boyfriend. He settled in as a two-foot dick and she adoringly stared at him, her cute little Jeff-Cock.
Jeff continued to stare at the slick lips in front of him. In addition to Jenny's own wetness, Jeff's semen was beginning to leak out. Her wet pussy was getting even wetter as it slid out and coated her lips. But as Jeff stared, he realized something else was changing. The ceiling was getting further way! Was he not fully flaccid yet? Is it possible he could be getting even softer?
Jenny also noticed Jeff shrinking but from her vantage point could tell his shape wasn't changing, just his size. She panicked as she realized she was keeping pace, also shrinking right in the middle of the bed. What was going on? She hadn't programed in this change... they were supposed to become human again! Was the program making them tiny humans? She considered the idea but soon rejected the thought as she realized neither Jeff nor herself were changing. He was still a soft little dick and she was still a wet, leaky pussy.
And "little" was starting to feel more and more apt! Although it was impossible to say for sure, Jenny was pretty sure Jeff had finally settled down as a very-realistic sized cock, flopped sideways on the bed. And although she couldn't see herself, the fact that the bedroom looked like a sports stadium must have meant she was tiny too! A plain, regular 4" long pussy with a little eraser nub clit at the top.
Jenny wanted to scream, but instead, she started to black out. As her vision dimmed she wondered exactly what was going to happen to her and Jeff, the helpless pussy and cock with no owners.