Based on Archie Comics, since she broke both Tails and Sonic's hearts I though of doing something like this.
"As Fionna the Fox wakes up in a strange place, a familiar, yet annoying presence makes itself clear. She wakes up surprised, not knowing where she is she immediately see a face in front of her. Sally the Acorn is right there, looking down on her. Fionna tries to move - What is going on?- she asks as she fails to move. Golder rings trapp her hands on a wooden table. She is nude and bent over in the middle of a luxurious place. Sally clears her throat - Hello, Fionna. Hope you didnβt mind the ride, interdimensional travel is quite an experience. But you are here now - before Sally can continue Fionna interrupts- So you kidnapped me into another universe? Why? And why the fuck am I naked?- Sally takes a deep breath and keeps talking - As I said, you are here now. Sonic and Tails convinced me to help them in this endeavor, but I guess I should cut right to the point. You are gonna pay with your body, understand? Tails is going to let go of some steam with you if you know what I mean. That is why you are trapped in that position, and without your clothes. Fionna rolls her eyes at Sally -Great, now the little dude is going to fail at penetrating with his tiny dβ¦ - As Fionna looks Up she sees Tails standing on the table with a massive erection on his hand. His cock is throbbing and leaking precump, Tails just looks at her with an evil grin. - Holy shit! Where did you get that thing!? How!? That is freaking huge!- Tails grabs his dick and plays with it slowly - Thank you, I'm glad you like it. -"