Jen and Cassie could no longer tell how long they had been in their sexual haze. The one thing they did know, however, was that it was Cassie's turn to cum in Jennifer (okay, two things: be it some magical compulsion, or the way the glass box restricted their movement, they were unable to cum anywhere else). Additionally, as the time had gone on, Jen and Cassie's feelings about what they had to do turned from disgust to arousal to craving.
“Oh- god- yes- Cassie- cum- inside- me!” Jennifer screamed.
And as it had been for hours now, they both came at once. Their massive breasts pressed against one another. Jennifer's vagina clamped down onto Cassie's member as Cassie pumped yet another load into Jenny's too-tight pussy. They both came as hard as they ever have in their lives, both simultaneously, screaming into the device that made their screams fill the halls. When they both regained consciousness, Jennifer was once again in possession of their penis. Jennifer resumed her endless pounding of her lover.
“I- love- you...” Jennifer whispered.
“I- love- you- too,” moaned Cassie.
Well into their next hour, mere minutes before their hourly climax, a familiar face knocked on their glass prison. It was Kyle.
“Well you two seem to be getting along famously,” Kyle smirked.
The two girls were too busy trying to cum to even care about what Kyle wanted. Kyle frowned, and in the blink of an eye, both girls were out of their prison, standing naked before their tormentor. Jennifer and Cassie screamed in sexual frustration. Jennifer's cock throbbed, demanding release. Almost immediately Cassie got onto her back, with Jenn getting on top of her to work furiously to their release.
“I wanted to tell you two that your newfound friendship warmed my heart. As such, I am going to let you both go.”
“Uh- what- really?” the girls cried out in unison as they continued thrusting.
“Oh, of course. But I think I like you two helping one another out... So, as part of the conditions of your release, I think you two will need to continue helping one another out.” stated Kyle.
Jenn and Cassie kept working to their climax.
“You two are now made for each other. That cock of yours will fit you two like a glove. You both will have your vaginas; it's been right below your cock when you trade. You will both cum simultaneously, regardless if you two are having sex with one another or not. When you two cum, the cock will transfer to the other girl.”
Kyle continued as the girls began screaming. “Oh, I'd be careful with that cock of yours, ladies. Once you insert it into a woman, you won't be able to withdraw it until you cum inside her. And while you two will only have a normal chance of getting pregnant from it, your seed will be super potent to every other woman you may fuck... May even cause a few... changes to them as well.” Kyle seemed very pleased with himself.
Jennifer was nearly there, as was Cassie. Jennifer's relentless pounding was met with Cassie's grinding against her, legs wrapped tightly around her.
“Since I love how you two work together, you two will have to fuck at least once an hour. If not every hour, then on the hour. Don't worry, you will always be able to find a partner if you can't get to each other. May want to be close by... I'll be around to check on you both. You'll have such wonderful daughters I'm sure!” Kyle laughed as he walked away and out of sight.
Jennifer and Cassie were in the throes of a mind-shattering orgasm as he left.