Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/247548.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      Multi
  Fandom:
      Adventure_Time
  Relationship:
      Finn/Marshall_Lee/Prince_Gumball
  Character:
      Finn, Marshall_Lee, Prince_Gumball, Jake, BMO
  Additional Tags:
      Threesome_-_M/M/M, Anal_Sex, Anal_Play, Dubious_Consent, Genderswap, Kink
      Meme
  Stats:
      Published: 2011-08-31 Words: 2366
****** threesome time ******
by enemy_xands
Summary
     Kink meme fill. Prompt: Finn somehow gets teleported into the
     genderbent dimension where he meets up with Marshall Lee and Prince
     Gumball, who are both immediately smitten with him and double team
     him.
Notes
     For the new-ish Adventure Time Kink Meme (http://
     makeoutpoint.livejournal.com/) which is the best thing ever, and I
     can't say no to genderswapped!Adventure Time ever. And I'm just gonna
     warn for typos now.
The tree house was unusually silent that afternoon. Finn laid sprawled out on
the floor blowing a feather over his head while Jake quietly sipped from his
mug of tea on the couch. Beemo wandered in and sat wordlessly on the table but
Finn and Jake ignored him. After a longer stretch of silence, Finn flew up in
frustration.
“This bites!” he exclaimed. Jake and BMO looked at him.
“Yeah, things are pretty dull,” Jake said and took another sip. “But if you
wait long enough, somethin' fun will happen."
“What makes you so sure?”
Jake shrugged. “Just the way these things always happen, I guess.”
Finn waited, but for what he didn’t know. He looked around as if the
personification of adventure and fun was hiding just around the corner.
However, after a few disappointing minutes he slumped back down and glowered at
Jake.
“Nothin’.”
Jake noisily sipped at the remains of his tea and stretched his arm out to
flick Finn’s nose. Finn sneezed and swatted at him.
“Finn, if you’re so bored why don’t you go make your own fun? You’re harshing
me and BMO’s mellow.”
Finn looked from Jake to BMO and back to the ceiling and then sighed. “Sorry,
guys.”
“Beemo has no mellow to harsh,” the little game system said.
“Sure you do,” Jake insisted. He raised his arms and curled them into spirals,
his body undulating like a living abstract painting. “Everyone has a mellow.
Just sit still and soak in the ambiance.”
BMO went silent and sat still. “I feel it! Beemo has a mellow! It is like
floating!”
“There ya go! I feel like I’m floatin’ too!”
Finn laughed. “Yeah, me too! It’s kind of weird, like we’re all brain-synched.”
“It’s gettin' stronger! Uh-oh...” Jake glanced over at his tea cup and noticed
it was rolling on the ground towards the kitchen at a breakneck pace. He
stretched his arm to grab it but it kept building momentum until it flew just
out of his grasp. Next, the table, sofa, and rug followed the cup into the
kitchen. Finn struggled to sit up before being jerked up by some unseen force.
“Guys! What’s going on?”
Jake yelled over BMO and Finn's panicked cries. Jake anchored himself on a
stump and wrapped his free hand around BMO and grabbed his teacup with one of
his feet. “Finn! My foooot!”
Finn grabbed hold of Jake’s foot as he slid into the kitchen. Jake’s stretchy
limb let out like a fishing reel and Finn found himself flying into the
kitchen—or what was left of it. Everything had been sucked out, and the culprit
was a spinning black vortex in an otherwise undisturbed sky. With a final snap
of Jake’s leg, Finn’s eyes widened and he yelped wildly as he was sucked
inside. He fell through the darkness for what seemed like eternity, until the
bottomless pit finally opened up under him to reveal blue sky. He slid out and
landed on the roof of a building; sharp pain shot up through his side and he
faintly noted the taste of blood in his mouth as he slid off the round dome. He
landed in the grass at a pair of feet and a pair of hooves.
“… Whoops,” he heard before he blacked out.
~~~~
“Ugh…”
The boy twitched and stirred in the bed, his eyes opening slowly to the bright
lights. He winced and groaned again before his ears honed in on the whispers
surrounding him.
“Oh, you’re awake!” said a guy—clearly a guy. Somewhere, a horse clacked its
hooves. Finn sat up and looked around.
The room, it… it looked exactly like Princess Bubblegum’s room, except less…
girly. Peebles’ room was decorated in soft pinks and purples but this room was
full of dark magentas and hard reds like a schizophrenic attempt at
masculinity. It almost literally burned his eyeballs. He whipped around and saw
a pink guy who also looked almost exactly like Princess Bubblegum except… not
at all. A prince judging by his crown, dressed in the same pinks and magentas
as his room. He was smiling nervously with laced fingers on his lap.
“Um, sorry about dragging you here. Me and Lord Monochromicorn were testing the
theory of Einstein-Rosen bridges and—well, it was a success…!” A nervous laugh.
Finn peered behind the prince and saw a long, black unicorn with a grey mane.
Two of his hooves clopped on the ground like Morse code, and he gave the prince
a skeptical look (as a unicorn could manage, anyhow).
“Where the math am I?!” Finn screamed, throwing the covers off the bed and
standing up on the bed. The prince and the unicorn looked at him blankly.
“Why, you’re in the Candy Kingdom. I’m Prince Gumball, and this is my steed,
Lord Monochromicorn!”
Finn sat back on the bed and gave Prince Gumball and his horse another glance.
The jumbled pieces of his brain began shifting back in place and it hurt, but
it was the only way to make sense of things. Fortunately, Prince Gumball sensed
his distress.
“It seems like we’ve pulled you from an alternate universe where everything is
the opposite,” he stated matter-of-factly. “You do look a lot like Fionna. Let
me guess, you’re… Finnegan?”
“Close enough. I’m Finn, and I’m the hero of Ooo!”
Prince Gumball nodded. “I see. Then I must have a female counterpart in your
world like you have a female one here. That’s absolutely fascinating! If you
don’t mind Finn,” Prince Gumball’s pink face reddened, “I’d like to keep you
here and… study.”
Lord Monochromicorn tapped his hooves, prompting a nudge from Prince Gumball.
The prince whispered something Finn couldn’t hear and Lord Monochromicorn
slipped out the window and flew off. Finn stared blankly at the scene then
shrugged.
“Well, okay I guess, but… I need to get home soon, so—”
“Great!”
Prince Gumball grabbed Finn and whisked him off the bed and out of the bedroom,
down the long spiraling hallway and up a spiral staircase until they were on
the roof again. Finn could even see the still bloodied and cracked spot where
he landed; he winced, but Prince Gumball didn’t seem to notice. Instead, he was
kneeling in front of Finn, barely able to contain his excitement. Finn looked
around with growing apprehension.
“Um, why are we on the roof?”
“My lab is full,” the Prince said flippantly as he ran his hands under Finn’s
shirt. The sensation made Finn shudder, and he felt like something was vaguely
wrong about all this, but it felt good at the same time…
A shadow passed overhead. Prince Gumball didn’t seem to notice and placed a
kiss on Finn’s belly. Finn gasped and began wriggling.
“Prince-—wait!”
A pair of feet dropped softly behind Finn. He tried to get a look at the person
but Prince Gumball was trying to pin him down.
“You’re late,” Prince Gumball muttered to the figure.
“Your horse didn’t mention what a little cutie you had.”
The guy leaned into sight. Finn wasn’t totally unsurprised that the guy looked
sort of like Marceline. A boy Marceline was all he needed right now. The
boy!Marceline had shorter hair and wore a red plaid shirt and an unnerving
grin. He was staring at Prince Gumball while addressing Finn.
“So you’re our little experiment today,” he said. His voice was low, a little
gravelly, and it made Finn’s tummy do weird flips. He swallowed dryly and
looked between the two guys.
“Gumball said he was going to study me but I need to be getting back soon—”
“Oh, yeah.” Prince Gumball barely suppressed a giggle. “Marshall has to study
you, too. He’s my assistant. Just do what he says and we’ll let you go soon.”
Finn gulped again, but before he could say anything else Marshall smooshed his
lips in a kiss. Finn’s face burned—he hadn’t even kissed a girl yet, let alone
a boy! He was saving that! And now the vampire’s tongue was wriggling around in
his mouth, wet and coppery and pushing against his tongue and cheeks.
Meanwhile, Gumball was nipping at Finn’s chest, leaving a trail of red
splotches as he made his way down the boy’s stomach. Marshall pulled away with
a wet pop and winked at Gumball.
“His mouth’s okay.”
“Really? Lemme see.”
Prince Gumball sat up and kissed Finn. Marshall’s hands dipped down into the
waist band of Finn’s pants and shoved them down. Finn’s protests were muffled
by Prince Gumball’s lips, who then raised the boy’s hips so Marshall could
slide the shorts off. Finn kicked his leg out when Marshall found the small but
growing bulge in his underwear, shuddered when he began massaging it. Marshall
grinned, then pulled Gumball away from Finn’s lips. Gumball looked
disappointed, but his face brightened a little when Marshall pointed down.
“Ready, Dr. Science?” Marshall asked teasingly. Gumball pinched him and pulled
his own shirt off. Marshall followed suit and sat behind Finn to hold his legs
open. Finn shivered again even though his body was growing hotter every second,
every agonizing inch as Gumball slid his underwear down.
“Guys, please, come on, this is—”
“Ready for a full body check?” Marshall interrupted. Gumball nodded and
stripped Finn’s undies off, throwing them off the roof. Finn gasped, both at
the loss of his last protection and the sensation of Gumball’s mouth around his
cock. Gumball sucked him delicately and Marshall spread his legs a little
wider, letting Finn rub against his clothed erection. Finn thrust up in shock
but ended up moaning against his will as he pushed himself deeper into the warm
wetness. Gumball gagged a little and Marshall laughed at him.
“Hey Prince, remember what we were talkin’ about earlier? I double-dare you to
check down there.”
“Mmf?” Gumball popped Finn’s cock out of his mouth. “Ew, no Marshall, that’s
gross.”
“Come on, don’t be a wuss. Just try it.”
Gumball pouted a little, but inched Finn’s bottom up further and spread his
cheeks. He closed his eyes and tentatively licked around Finn’s hole, dipping
his tongue in a little and moving it around. Above him, Finn shrieked and
Marshall grunted. Gumball quickly sat up again, panting.
“I didn’t think you’d really do it. Was it like a girl?”
“It wasn’t that bad I guess, but let’s do it now.”
“Let’s swap places, I know you wanna bottom.” Marshall gave Gumball a
mischievous grin, which the prince balked at. They switched places, holding the
trembling Finn on all fours between the two of them.
“Wh… what are we gonna do now?” Finn asked, his voice cracking. Beneath him,
Gumball stripped his pants off and spread his legs open. His hard cock bounced
against his stomach, leaking a clear fluid all over. He wet his fingers and
stuck them in his own hole, stretching himself out.
“You have to put your thing in me,” he said simply. Finn gulped and found
himself pushed from behind by Marshall. Marshall unzipped his pants and took
out his own cock. Finn looked behind him and saw the vampire’s hand was
glistening, and he rubbed whatever it was on his shaft. Marshall then grabbed
Finn’s hips and lined him up.
“Are you going to be alright with no lube?” Marshall asked Gumball, suddenly
concerned. Gumball nodded stubbornly and spread his legs wider. “Okay kid, this
is going to hurt a little… at first.”
Finn fell forward between Gumball’s legs. The prince grabbed his cock and
slowly eased it into himself, wincing at the pain. Finn moaned loudly and
panted at the sensation, thrusting the rest of the way in. Gumball let out an
echoing moan and grabbed Finn’s hat to draw him in for a kiss. Behind him,
Marshall leaned in and eased his own cock inside the boy adventurer. It was
much tighter than he was used to, but so good—he stood still and savored it for
a moment, savored Gumball’s moans and Finn’s squeaks of discomfort.
After allowing Finn to adjust, Marshall began thrusting, first trying to match
Finn’s own erratic rhythm before finally going at his own hectic pace. The two
of them eventually synched up to Gumball’s movements until all three of them
were crying out in unison. Finn came far too fast—bless his young heart—and
collapsed sweaty and spent on Gumball’s chest. He frowned, but saw that
Marshall was still moving inside the boy, working to reach his own orgasm.
Gumball jerked his cock in time with Marshall until both of them came with a
shout. Marshall slumped over Finn, panting and exhausted, but smiling down at
the Prince.
“I think he’s all checked out,” he said lazily. “Shall we send him home, my
liege?”
“Quit it, Marshall,” Gumball said with another cute pout.
He whistled an airy tune and patted his belly; a moment later, Lord
Monochromicorn swooped in. He looped himself in the sky and created another
dark wormhole. Before Finn could register what was happening through his
grogginess, he was sucked in with a yelp that reverberated throughout the
kingdom.
“…Should we have at least sent him back with clothes?” Prince Gumball wondered
out loud. He looked over at Marshall, who shrugged nonchalantly.
~~~~~~
Back in Ooo—the alternate one, anyway (or was the other Ooo the alternative
dimension? Who knew.)—Finn fell out of the sky again and onto something soft
and cushy this time. He looked and saw Jake was shrinking down to his normal
dog-size, gently depositing Finn on the ground.
“Finn! Where’d you go, man? BMO’s been worried sick that his mellow killed
you!” A beat. “And so have I!”
“I… don’t really know,” Finn said, clutching his head. “I think I got warped
into an alternate dimension.”
“Was it a dimension where people ran around naked and smelled funny? Because
you’re naked and you smell funny.”
“It was full of weird people.”
Jake stretched himself so he could climb back in the tree house in a single
bound with Finn hoisted over his shoulder. “Well, you can tell me all about it
after we get you a bath, and some clothes. Oh, and a burrito!”
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