Sarah scrolled through the list of fetishes on the Chronivac, and she found one that read 'Conjoinment'. She didn't quite know what it meant, so she decided she wanted to try it out with Jeff. She selected it and hit apply.
Suddenly, Sarah started having thoughts of sharing a body with another person. Specifically, her boyfriend Jeff. She got aroused at the thought, and used the Chronivac to merge her and Jeff's body together. She wondered what their body would look like when they fused. Jeff came back from the bathroom, and opened the door just as Sarah hit apply once more. His vision blacked out, and the last thing he felt was the sensation of his body being pulled.
When he woke up, his body felt strange; it felt heavier than normal. He tried to lift his right arm, only to find it wouldn't respond to his brain's commands. He looked down to see a pair of breasts on his chest, beyond that, a pair of plump pussy lips.
'Sarah!' He called out, not knowing where she went. Suddenly he heard a noise to his right.
'Huh...' Sarah said, groggily. Jeff turned to the source of his girlfriend's voice. She was very close to his face, and seemed to have just woken up too. Jeff looked down, and saw that both their necks shared the same torso, making him gasp.
'What did you do?' Jeff asked, his eyes wide.
'We share a body now, Jeff,' Sarah answered, kissing her boyfriend's lips, using her side's hand to turn his head. The kiss felt weird; Jeff could feel both his own, and his girlfriend's mouths.
'Do you like it?' Sarah asked. Jeff was about to protest, but he felt a strange tingling between his legs; their new shared pussy was dampening. Their body was getting horny at being fused together. It seemed they now shared attractions, due to their pussy reacting to both their desires.
Sarah touched their pussy, sending a jolt of pleasure through their fused body. They both moaned simultaneously. Jeff had never felt this pleasure before.
'Keep going,' he groaned, as his arm groped their left breast. Sarah stuck more fingers in their pussy, thrusting them in and out. The experience of something penetrating his crotch was alien to Jeff, but he was enjoying it, maybe even more than having a cock. Jeff continued rubbing their breast, as their nipples hardened.
Sarah continued fingerfucking their wet pussy, as they reached climax. Jeff's breathing become faster, and Sarah moaned louder. Suddenly, their thighs began to shake as their shared pussy spasmed, sending waves of pleasure through their body. Jeff's mind went blank, having experienced pleasure like never before. Apparently, their new body was a squirter, as their pussy shot hot girlcum onto Jeff's bedsheets.
After coming to their senses, they coordinated their legs to stand up and move towards the mirror, falling over just once. They were now around 7 feet tall, and their breasts were very large; Sarah estimated they were around an F-cup. Their body was slightly pudgy around the waist, and their ass was amazingly large, probably owing to the extra mass from fusing two grown humans.
Jeff, originally being against this, began to like it as he stared at their beautiful visage. He was now much closer to his girlfriend, both literally and figuratively. As he turned his head to kiss the other head on their shoulders, he began to think about the implications of having this large, female body.
Sarah loved her larger body, even if it wasn't much different from her original one. She especially loved having her boyfriend on her shoulder. She was glad she could share the pleasures of the female body with him. As she idly rubbed their pussy, she considered asking Jeff if they could go out like this.