Benjamin's nose was stuck between Brianna's ass, kneeling in the middle of a triangular piece of art that was way too uncomfortable to be intended for this. It was made of painted red panels covering a mechanical beam that had been welded and twisted to try and form a 3 dimensional shape. Unfortunately, without the chronivac, the impossible shape was only visible from a specific angle, and this had pretty much ruined the illusion.
Brianna was currently the owner of a lizard tail with soft, white furs, and from the attention it was getting she knew Freya must have added a scent gland in there. He was really into it, and she was starting to sweat from the strain of keeping on. The next transformation didn't help either, as her feet started to get the same white fur, her toes forming together into a hoof. Benjamin shifted his grasp on her ankle, trying to find the right ankle as her knees reversed, and then lowered her head as a pair of spiraling horns broke out of her skull. They came in facing forward, but slowly shifted back and down as Freya adjusted their position.
Freya mused as she adjusted the chronivac. She thought being balanced precariously would heighten the experience, but while the awkward pose seemed to be working for Benjamin, it didn't seem to be for her sister. She wondered how to fix this problem. Her hand lowering to her belly. She couldn't feel anything outside but couldn't help herself from poking at the acrylic mass filling her extended womb.
There'd been an accident, when they left the lavatory, after which they'd discovered this weight was resting on her bladder, greatly sensitizing it and reducing it in size. Benjamin had solved it by removing her bladder entirely; now she had two small nostrils inside each leg which were constantly exhaling air from a gas bladder behind her stomach. It carried away her body's excess moisture, though it did mean she'd always have to make sure her nether regions were.. well ventilated. So now she was wearing a leather skirt made of dozens of separate pleats. Kind of made her look like a roman warrior.
Hmm.. that gave her an idea. She brought up the chronovac again and set another change. Brianna slipped, as she had opened her hands in surprise when they became full of a white, sticky substance. But she didn't fall, as sticky silk now held her in place.
Benjamin drew back, slapping her ass to get her to turn over, which she did. She spun more silk from her hands, this time anchoring herself to the top of the structure, but Benjamin was having trouble penetrating her since she was too far away from the edge. Brianna took the moment to experiment with spinning a more elaborate web, and soon had a suitably hexagonal-shaped web to lean back in. She thrust her hips forward, past the edge to give better access, and he eagerly dove in. As soon as he was it bloomed inside of her, splitting apart into six prongs that extended and then flattened to the bottom of her uterus holding him firmly, deeply in.
Her vagina tightened in surprise as she felt this strange intruder, but the surprises weren't done yet. Benjamin was staring down at his naked chest as giant gold sperm were emerging from a cavity between his breasts. The first few went wide and started squirming on the floor; one of them a bit too close to Freya who stomped on it with her heels. Then he adjusted his angle and they started landing between Brianna's breasts, and snaking their way down her tube top to her belly button where, they wiggled in. Both of them convulsed in pleasure as this occurred over the next half an hour; Benjamin pushing to get them out and Freya, finding them all too ticklish, laughing hysterically as they spun around around before they finally pushed their way in. Benjamin tried to withdraw several times, but was locked in place by his grappling penis, and when he tried to stop them, the giant sperm just wiggled out of his hand. Freya meanwhile was running around the whole time, stomping any stragglers that tried to get away in her 4" heel boots, leaving a golden mess of popped scales and detached flopping tails.