Fionna and Cake ran together, bursting with adrenaline and excitement as Cake's new powers and the revelation that they'd been right about being more important than the mundane world that had been created by Simon's being cured. They absolutely weren't about to go back to that now, so had fled down the sprawling hallways of Prismo's time room.
They were… very lost. But they didn't care. Cake had occupied herself with experimentally shapeshifting, seeing what crazy forms she could twist herself into and enjoying the lack of pain as her body twisted at odd angles.
Fionna blushed hard at the form Cake ultimately settled on, one about a foot taller than Fionna and significantly thiccer. "You can't stay like that Cake," Fionna said sheepishly, attempting to ignore her cock's immediate response to the form, "You look like a damn milf!"
"And how's that bad~?" Cake questioned teasingly, putting her hands behind her head and puffing her chest out seductively. Fionna blushed harder as she realized Cake actually had shapeshifted herself real tits; a real body, so to speak.
"Because you're a cat!" She explained, turning away and trying not to look.
Cake smirked, hands stretching over to turn her around, "Not anymore I'm not! I'm a magical creature now, I can do whatever I want, and so can you~" Her hands moved down, taking Fionna's new shorts with them.
"C-Cake no!" Fionna yelped, stumbling back and landing on her ass.
Cake let herself fall forward, landing on top of Fionna with her shapeshifted breasts landing on/around Fionna's newly exposed hard-on. She sucked in air through her teeth as she felt Cake press her hands together around them.
Fionna shuddered as she felt Cake's shapeshifted breasts squeeze around her cock, "F-fuuuuck that does actually feel pretty good~"
"See~?" Cake snickered as she continued to stroke her, "Just relax and let me test this new body out~"
Fionna bit the inside of her cheek, forcing the idea of her being a cat to the back of her mind. Cat's can't walk on two legs like Cake was now, nor could they talk, shapeshift, and give amazing titfucks. She was more than a cat now.
Cake squeezed harder around Fionna's cock, wrapping her lips around her tip. She'd never done anything remotely like this, but had seen a surprising amount from Fionna and her exs, and did a better job right off the bat then Fionna felt like she should have been able to.
She'd let herself ignore it until now, but she was still pent up from getting close and then having it ripped away back with the ice cream lady. Cake's warm, soft pumping of her dick slowly milked the orgasm back out of her.
Cake purred as she swallowed Fionna's seed, pulling up and moving forward to straddle her, "Come on, I've seen how long you can go, I know you aren't done yet~"
It was true, her stiffness hadn't gone down at all. Much of a curse as it had usually felt like back in her normal world, she was suddenly glad for her boundless sexual stamina. Fionna's hands moved to Cake's hips, pulling them down hard as her own thrust up to meet her.
Cake gasped at the feeling as Fionna practically hilted herself inside the milfy shapeshifted body. Her stretching body seemed to make her immune to any pain such roughness would usually create, her body able to simply stretch and squeeze back down around her cock as she buried it deeper inside of her.
Lacking said pain left only waves of intense and unfamiliar pleasure. Fionna soon realized that Cake was actually outpacing her, her shapeshifted body evidently physically stronger than Fionna; at least now that Cake had lost a bit of control. Her hips moved like a blur as she took Fionna to the base with ease.
Not wanting to be outdone, Fionna got a firm grip on Cake, and stood while still keeping her on her cock, "You feel so fucking tight Cake~" Fionna groaned, continuing to bounce the magical cat woman on her cock with each step.
Cake's tail wrapped around Fionna like a harness, her legs and arms locking around her waist and torso, "I-I can make it even tighter~" Cake moaned into Fionna's ear, focusing on her body to squeeze and stroke Fionna inside, her already amazing pussy seeming to suck Fionna like and work her cock with the control of a blowjob.
It was a kind of pleasure that literally couldn't exist without her powers, and it almost immediately brought her over the edge; the constriction of her body drawing the seed deep into her body.
She really hoped she wasn't also magically able to get pregnant. But even as that thought encouraged her to stop, that same fire she'd felt back in her boring world hit her again like she'd been hit with an aphrodisiac.
She could tell from how Cake's body was clenching around her that she felt it too. It was like their bodies or souls or something were remembering and craving something their minds couldn't anymore.
Fionna turned, pinning Cake to the nearby wall and starting to drill into her with more strength than she'd realized she had. Seems Prismo had given her powers after all, if only the sort she could have gotten from a few years in the gym.
She buried her face in Cake's chest, sucking and teasing them with her teeth as her cock hit as deep as their biology would allow with each passionate thrust.
Fionna wasn't sure time existed in that place, but was pretty sure she and Cake were fucking for hours in that hallway, and somehow still weren't exhausted when they were done.
They took each other's hands and took off running down the hallway towards what they hoped to be an exit, high on their new magic and the afterglow of their fun, "Adventure Time!"
…oh goddammit this is the same room as before.
"Sup." Prismo greeted, Simon face palming.