“Can I ask?” Ace said, kind of muffled as his mouth twisted into awkward I’m-totally-not-smiling shapes and his eyes danced. “I swear I won’t judge your an—”

Nobody elbowed anybody this time; Ace had cut off himself because, probably, he would’ve burst out laughing if he’d continued. Degrees of dread increased by tenfold, and Marco, because he was an experienced adult who practiced things like mental health, turned on his heel and walked away toward the afterdeck.

“—aw, c’mon Marco!”

“You really don’t wanna walk any further than that,” Sabo called, “if you don’t want your crewmates hearing us ask about your self-lubricating asshole—”

Marco has never truly regretted resuscitating Sabo in Ace’s life until now. Such a pity that Ace loved a guy that was about to die in 0.3 seconds when Marco’s talons snapped his fucking neck.

Sabo danced out of the way of Marco’s sudden charge, and then Ace got in the way. Marco never knew fire could burn in a way that so closely approximated a shit-eating grin. Haki flashed, because Marco was out for blood dammit, but the trouble twins were hardly an easy force to contend with. They have Marco bracketed in a second, each one ready to launch an offense the second the other needed to fly into a defense.

And they were both still fucking smiling—

“Marco don’t get mad!” Ace yelped as he tried to tackle Marco around the waist and Marco flipped them both into the sky. Ace would’ve been unceremoniously kicked into the ocean, had Sabo not taken the moment to hop up as well, wrapping himself in a very koala-like fashion around Marco’s torso to prevent any pivoting momentum.

“Yeah Marco don’t get mad,” Sabo repeated, and got a wing smack to the side of his head for his cheek. Also, for his fingers dipping under the back of Marco’s pants, as if aiming to touch—

Marco went full phoenix (which did not help his biological situation but that couldn’t be helped right now) and promptly dumped the two demon brothers onto the deck. Crew mates were vaguely looking on, but fights at this scale were hardly worth the effort of rubbernecking, especially when they’ve all learned one-too-many times that playing peanut gallery to a Marco-Ace-and-Sabo fight could quickly descend into something else they’d never come to see.

In the middle of choosing between permanent migration and permanent self-immolation, Marco was bombarded with a wrap of flame a lot like a hug around his whole body. Ace attacked with enough force to also bring Marco down, and keep him down, pinned to the deck by the joint perseverance of two boys who obviously grew up in the jungle hunting wild beasts for survival.

“Look,” Ace panted into Marco’s beaked face, because they couldn’t make him talk if he stubbornly remained a bird. “You obviously don’t have to tell us, if you don’t want.”

And you are obviously as big of a liar as your brother, Marco wanted to howl, but that would require turning human, which would be playing right into their devious little hands, and Sabo had been tasked with pinning down Marco’s talons but now he’s got an odd little glint in his eyes as he contemplated the limbs that he was gripping and what those limbs were connected to and—

Marco transformed back to full-human in a flash of bright blue, and then promptly kneed Sabo in the face.

“Ow,” Sabo said once more, plaintively gripping his nose.

“It is an evolutionary biological trait,” Marco hissed, hopelessly red from the entire neck up. Hell, he didn’t know which was hotter, his skin or Ace’s hand, still half-flames, gripping his arms (which definitely was not helping with the situation down under). “And I despise both of you yoi.”

“That’s—”

“—fine,” Sabo interrupted Ace nasally, eyes way too shiny for the pathological mind underneath. “But just fucking tell us why you get wet, Marco. Y’know, evolutionarily speaking.”

“I would really,” Marco said, the picture of abject misery, “rather die.”

“Not like that’s ever stopped—Oh.” Fucking Ace. He was almost always the spanner in the works for moments like this, because Sabo’s fanged curiosity could be batted off with a careful defense but Ace’s intuition was merciless as no other. And he wasn’t even nasty about it like Sabo, just open and friendly enough to lull Marco into a false sense of security until Marco’s divulged everything.

“Is this like,” Ace asked, “a bird thing?”

It would be so undignified to try to thrash away like a fish caught on land. Marco seriously contemplated it though, as Sabo’s grin gained teeth.

“Oh Marco,” Sabo sighed breathlessly, “do you have anal gland secretions—”

Marco thrashed. Fuck dignity; it’s not like he’d have any left if he just lied there anyways. He went for Ace first this time, headbutting the guy (of course with haki) and then going for Sabo’s throat. He had windpipe in hand ready to wring when a familiar burst of heat hit his very human back, igniting the blue feather-flames and shooting in a by-now-predictable path down to Marco’s—

“Will you stop that,” Marco snapped, twisting to toss Ace off (not fucking like that) once more. The way he instinctively kept his hip from impacting the ground though, as he rolled uncomfortable into another defensive position, had the unfortunate side effect of tipping Sabo off.

“Oh, so this isn’t just a bird thing, it’s a fire thing. It’s an Ace thing.”

Ace had already hopped back to his feet, no worse for the wear. He wore a confused frown.

“What’s an Ace thing? Marco? Wait, I make you wet?”

Giving up on his pride and his life entirely, Marco slammed his head back into the deck, starfishing onto the ground.

“I don’t get wet,” he answered hollowly, because of all the ways they told him being a pirate on the Grand Line would kill him, nobody’s ever warned him about the twin devils and their persistent fucking questions. “It’s oil, yoi. Phoenixes secret flammable oil that then needs to be preened onto feathers.”

“And you produce those oils…” Ace said.

“Anally,” Sabo finished. Marco nodded, and felt himself die right then and there. Death by humiliation was worse than death by exsanguination, but still somehow better than disembowelment. “Well. That’s convenient.”

“It happens all the time,” because Marco might as well make this death as total as posible, “but the presence of fire encourages more secretions, yes.”

Ace’s face appeared in Marco’s vision, coming over to hove above Marco’s prone body. He wasn’t smiling anymore, really.

“Listen,” he said quite solemnly, “I’m not not-turned on.”

“Yup,” Sabo said, popping the P as he joined Ace’s side, eyeing Marco’s crotchal region. “I’m a total romantic; I can definitely still get it up for your flammable ass grease.”