While writing this story, I had to watch and re-watch the Fionna and Cake episodes multiple times, and as I did, I got more and more pissed off that it isn't canon. Sure it's canon to the multiverse, but that doesn't count, everything is canon to the fucking multiverse. Thoughts?
Fionna and Cake had been exploring the new world for a few days now, and a lot of it was different. There were still a few things they recognized and understood about the place, mostly the locations and the names of them, but the people living in them were more often than not different than Fionna and Cake knew, either a different gender or missing from the world entirely. Most strange of all, was that the majority of people seemed to have switched the name of the world from Aaa to Ooo. It just didn't sound right to Fionna and Cake.
Unfortunately, as much as certain parts of the world changed, other parts didn't change enough. Fionna and Cake had been exploring for hours on end in search of some magic to fix Fionna or at least for some explanation about what had happened to the world. Not only did they not find either of their goals, on the fourth day out, they were attacked by Ice Queen.
"You think you can make all the princes vanish huh?!" Ice Queen shrieked at Fionna, evidently assuming the absence of all the male was somehow Fionna's fault, not seeming to make the connection that Fionna would also be upset about Prince Gumball, Martial Lee, and Flame Prince's disappearances.
"We didn't hide all the princes you dim witch." Cake shouted up at Ice Queen, receiving a hiss and blast of ice magic in return, Fionna blocked it with her sword, "let's just beat her up and get back to looking." Fionna said nonchalantly, Cake nodding and beginning to grow for battle.
The battle lasted a little longer than they usually did, closer to ten minutes than the usual five. Fionna and Cake were a bit tired and off their game from their traveling around Ooo, but even then they could, and indeed at one point did, defeat the Ice Queen in their sleep.
The fight ended with Fionna knocked Ice Queen out of the air with a sword slash, cutting her dress in the process and leaving her naked from the waist down when she landed hard on her face.
"Nice one, let's get back to searching." Cake said, Fionna nodding and putting away get sword. The two began to walk off, but Fionna stopped before they got more than one or two feet away. Fionna had gotten into the habit of looking back at Ice Queen after they fought, and wondering if Simona was in there somewhere, or if the crown's madness had erased her entirely. She never lingered on the thought for too long, thinking about Simona and Benji always made Fionna sad, and she never really knew how to deal with that.
This time though, when Fionna took her usual look back at Ice Queen, she saw her naked rump and pussy, exposed and lifted into the air slightly from how she had landed. Fionna's eyes lingered on this sight, her skirt starting to raise up slightly as her member stiffened.
Cake was only a few steps ahead when she turned her head and noticed that Fionna was staring at Ice Queen's half naked body, and got a mischievous grin when she saw the tent her skirt had become.
"Maybe we should take a little break instead~" Cake suggested, walking back over and pulling Fionna's skirt up slightly, freeing her member. She hadn't had any underwear she could comfortably wear with her new apendage, so she just hadn't worn any. It hadn't actually been a problem until now.
Fionna blushed deeply, "W-what? Right now? Ice Queen is, like, right there." She said, Cake nodding. "I know, she's what's gonna help you take your break~" Cake explained, stretching her arms over and removing the rest of the Ice Queen's clothes.
"What?! That's crazy!" Fionna stated, though the half-dazed Ice Queen seemed to take offense to it, "Crazy? Ha! I'm beautiful! You should be lucky you've got the chance to take me at all!" Ice Queen said, not seeming to fully grasp the current situation.
Fionna, for once, couldn't actually argue with her. With her loud dress torn off, the Ice Queen's body was actually rather beautiful, her blue skin looking soft and smooth over her surprisingly thin body and long legs.
"How about it? Just to relax for a bit before we keep looking," Cake said, "you're going to get rid of the thing soon anyway, and it's not like you haven't used it already, a LOT, what's the harm in a little more fun~?" Cake questioned, holding the Ice Queen's legs open, though she didn't need to, the Ice Queen had stopped struggling when she saw the size of Fionna's cock.
Admittedly, Fionna probably could have argued over this, but she realized she didn't want to. She wanted more fun with her cock before it vanished, and she wanted to fuck Ice Queen. Fionna ignored the burning red on her face and walked over, getting on her knees between Ice Queen's open legs and thrusting into her hard.
Ice Queen moaned immediately, likely not having had anything, let alone anything that big, inside her in a long time. Fionna's moans were quieter, but not for lack of pleasure, quite the opposite, it was flooding her senses and making it hard to react, nearly impossible to do anything but grip Ice Queen's hips and begin thrusting in more.
She'd done this before with Cake, and gotten passed the 'overwhelming pleasure' before, but it felt different with Ice Queen. Her insides were cold, but somehow, it felt incredible because of it. Not to mention Ice Queen moving her hips hard, wanting Fionna's cock deeper, harder inside her.
Before too long Ice Queen's moans were muffled when Cake straddled her face, the cat moaning as the Ice witch ate her out. "She's pretty good~" Cake moaned, sounding surprised. Ice Queen came after a few minutes, but it was another hour before the two were done with her.
Fionna started to pull out when she felt her climax building, knowing it was risky to finish inside her, but something primal flared up in her, and she thrust right back in, slamming her hips hard against Ice Queen's and cumming hard into her womb with a scream of pleasure.
Ice Queen blacked out from this, and Cake rose an eyebrow at this. Fionna blushed again, "I-It was an accident." She claimed, though she and Cake both knew that it hadn't been. Cake chuckled, "Sure, let's take her back to the tree house. I think she'll be kind of broken after that, and she'll definitely want more."