Zoro was not by nature a particularly horny guy. He's never drooled over people in bars, he's never owned porn magazines and never been obsessed with jerking off. Not that he doesn't do it but it's not something that's ever taken up a large portion of his mind.
With this in mind it's pretty unusual to find Roronoa Zoro, future world's greatest swordsman leaning over the edge of the ship, staring into the sea and furiously wondering how mermen have sex. It's so bad that he's contemplating asking someone on an island if they know.
Sanji perhaps didn't approve of his indelicate questioning in that nature but Zoro fucking knows that he wasn't imagining that look in the blonde's eyes. Well, the look in his eyes before he stuck his foot in it and pissed the blonde off enough to make him revert to threats of drowning.
Zoro bites his lip. He hadn't seen any kind of hard on going on there, and Sanji doesn't wear clothes. So... is it like... internal or something? Does his junk just come out to play when it's needed? Zoro shifts against the railing of the ship, Sanji's theoretical junk isn't the only thing that wants to play right now, he's got problems of his own. Again. For about the millionth time since he met the blonde Zoro heads below deck to sort out a problem that comes accompanied by mental imagery of sinuous abs, a long thick tail and dangerously blue eyes.
Sanji sinks teeth like razors into the jugular of the sea king. The thing thrashes, its giraffe neck and shark tail working double time to fend off it's furious attacker. Innocent is not a word one would usually use to describe monsters like sea kings but the giraffe-shark is hardly the cause of Sanji's current frustration. The blonde is looking for a brawl to vent off steam and a sea king is about the only thing these days that can put up that level of fight.
That and Zoro.
Oh the ways that Zoro has fought him in the past... Thick blunt fingers clawing at Sanji's skin, seeking purchase and gripping hard. The way Zoro uses all of himself to fight, he kicks with his legs but he uses his mouth too. Sanji remembers the feel of Zoro's teeth on his nipple and the way Zoro had changed from biting at him to that slow sensous lick and-
Sanji snarls and lashes his tail out, smacking it into the body of the giraffe-shark and sending it hurtling into a spire of rock.
Or the way that Zoro fights dirty, he'd put up a good fight right about now. Like the time that he'd pressed their mouths together and forced air through Sanji's gills to fend him off. What if things had gone differently? What if instead of leaving when Zoro was riling him before Sanji had just pinned the fucker to the deck and-
Hah. And what?
Zoro is human and Sanji is... is. Sanji isn't anything.
He just can't do what he wants because it's simply not possible. He's just taunting himself to think otherwise.
Sanji lets himself sink down to the sea floor whilst the giraffe-shark bleeds out into the water behind him. He curls his tail up under himself and hates himself for everything. He had just wanted some revenge and then... then things had to get fucking complicated. He buries his face in his hands and tries not to think about Zoro's jawline, or his smile, or the way his lips had brushed Sanji's ear fins.
Sanji is not following the Merry, he's not. It's just that fish like to gather under ships for the shade and the protection, Sanji happens to eat fish, so he's just travelling by a food source that's moving. That's all. It seems that the navigator of the ship is the beautiful redhead that Sanji had seen before and good god is she good. She reads the log pose like no one Sanji has ever seen. Not that he needs one of course. nevertheless no matter what it seems that Zoro's crew get into more trouble than Sanji had ever thought possible, the number of times they haul ass away from islands is thoroughly stupid and Sanji would smack anyone for saying that he's jealous when he lurks out of sight and watches the crew dismount onto another island and walk off inland to have an adventure that Sanji can't have with his tail instead of legs.
He's not jealous, he's not.
Despite his earlier threats Sanji hasn't managed to bring himself to drag Zoro into the ocean and drown him, which rather makes his other excuse to follow their ship a rather weak one. He's missed hundreds of opportunities for revenge and he's sure that Zoro has seen him more than a few times too. This however is one island that Sanji is not keen to get onto. Cold blooded though he is, Sanji draws the line at snow.
Always checking back on the ship at regular bases Sanji swims the coastline and, to his mortification, it's some time before he notices that Zoro is following him along it. Sanji peeks out of the water and sees Zoro looking right at him, his dark eyes boring into Sanji and making his insides squirm. Sanji can't help but follow and when Zoro turns away from the sea it's to walk along a river inlet to the island. Sanji decides to gather up his courage and speak, remembering that he's following Zoro so that he can kill him.
"You know I can drown you in a river just as well as I can in the sea! Why don't you come a little closer?" Sanji calls out, his head and shoulders above the water.
"Oh, so you can talk? I thought maybe you'd lost your voice since I last saw you, little mermaid." Zoro smirks at him and walks closer to the river.
The river finishes in at a waterfall which is surrounded by high rocks. He supposes that if Zoro wanted to pick somewhere by water to have a confrontation with Sanji but be able to get somewhere fast that Sanji couldn't follow then this would be the place. Zoro, ever surprising though, doesn't try to bait Sanji any more, he doesn't even point out that Sanji had no good comeback for that, he'd just floated there with his mouth open in mute outrage. What Zoro does do instead is take off his shoes, his bare toes then dipping into the water, sending little ripples across the surface that Sanji can feel in his gills.
"What on earth do you think you're doing?" Sanji asks flatly, his eyes widening still further when Zoro peels his shirt off in a ripple of tan flesh that makes Sanji's mouth water. Sanji ducks down under the water so just his eyes are visible, hoping that Zoro won't see the blush on his face.
"Training." Zoro answers easily and strides into the water.
Almost right away the ground below Zoro's feet falls away and he's out of his depth. Sanji falls beneath the surface and stares up at Zoro's body. He swims closer and hovers just an inch or two from Zoro's skin. He reaches out and wraps his arms around Zoro's waist, slow and secure. Zoro's hands come to rest on his forearms, not hard, just... resting there. Sanji flicks the tip of his tail and pulls Zoro just under the water, he could probably still get his face above the waterline if he strained his neck and tilted his head back. Instead though Zoro ducks his head under the water fully and blinks a few times before looking at Sanji under the water.
"I could drown you right now." Sanji says, keeping Zoro just where he is.
Zoro doesn't say anything, he can't, he's underwater and he rather foolishly never evolved the capability to talk underwater. Instead he just looks at Sanji. He doesn't fight him, he doesn't attack, he just looks at him.
Without Zoro fighting this whole thing is a little weird, it's like he's just embracing Zoro underwater. Zoro leans down a little more, his hands running up Sanji's bare arms. His face is right in front of Sanji's now, his hands tracing up to Sanji's jaw. He leans in and presses his lips against Sanji's. Sanji draws in a startled breath, expecting Zoro to force air through his gills again or something but instead Zoro doesn't, he just stays where he is.
"What the fuck was that?" Sanji demands, releasing Zoro in shock. Zoro hovers there under the surface for a moment or two, just looking at Sanji. There's no smug grin or 'gotcha' expression, he just looks at him. After a second or two, or perhaps a lifetime, Zoro kicks under the water and pushes himself back up to the surface.
Sanji follows and when he too breaches the surface he makes the same demand again.
"It's called a kiss." Zoro answers with a shrug. Then, as if nothing happened, Zoro turns and swims towards the waterfall.
"I know it was a kiss, why did you do it?!" Sanji snaps, following Zoro easily. No one swims faster than him, certainly not a human of all things.
"'cause I wanted to." Zoro replies and hauls himself out of the water and onto the rocks by the waterfall. His back is getting splashed and Sanji can't believe that Zoro is managing to stay upright under that.
"Why?" Sanji asks again, feeling numb.
Zoro leans forward out of the waterfall and grins down at Sanji, that's an expression that Sanji is a little more familiar with. The world doesn't feel so odd when Zoro is smirking at him like that, now he feels the need to drown Zoro again. Things are back on familiar currents once more.
"Quit asking me stupid questions and go on a date with me." Zoro says with a smile, his dark eyes sparkling.
Sanji floats there in numb shock and blinks at Zoro, his mouth not able to come up with words. Zoro kissed him and now he's asking Sanji on a date? No one... no one has ever done either of those things before. Oh, oh shit... that had been Sanji's first kiss. His hands fly to his lips and he flushes red from nose to the tips of his ear fins. He stares at Zoro and realises that Zoro is still waiting for a response. Is Zoro making fun of him? Mocking him?
"Do you ask out all the guys who try to kill you?" Sanji retorts, turning his anxiety into fury.
Zoro actually laughs at that, a warm sounding thing that's far from a mocking laugh that Sanji's heard before from people. It reaches his eyes and makes him light up.
"Nah, just the ones I really like. So, how about it?" Zoro asks, leaning on his knee to smile at him.
"Fuck you." Sanji hisses out. Zoro has to be mocking him, everyone else does. He feels his ears flatten against his head in anger. Oh he remembers what people are like, fishmen, merpeople, humans, they're all as bad as each other.
"Heh, maybe afterwards, if I can find out how all your parts work. You're the first merman I've ever seen you know." Zoro laughs at him.
Sanji hisses in rage and dives under the surface. With one powerful flick of his tail he's halfway out of the river and with a second he's back out into the cold salt water of the sea. He shoots down to the cold dark sea bed and wraps his arms around himself. He curls up and buries his face into his tail and tries to force away the memory of Zoro's gentle kiss, of the feel of his hands cupping Sanji's face.
He hates himself, he really does. As much as he hates Zoro for mocking him like that he hates himself even worse for wanting it. He tries to imagine a world where Zoro was being serious, where he could be normal and Zoro would actually want him. Where lewd innuendo like that could be a promise of something to come rather than a cruel barb. Sanji's sob reverberates off of the rocks around him. His tears meld instantly with the seawater around him, so perhaps in a way Sanji could claim that he never cried about this, not really.