Archive of Our Own

“I’m not taking a test .” 

Sanji rolls his eyes. Zoro never ceases to amaze him with his idiocy.

“It’s an exam, not a test, dimwit. Like one of Chopper’s checkups.”

“Then why isn’t Chopper giving me the fuckin’—” an exasperated handwave when he can’t remember the word, “dumb whatever test.”

Their doctor is a thorough one, meticulous in his care, as Zoro is well aware. Thankfully Sanji’s got a few decades before this particular inconsistency with the truth is at risk of being revealed.

Sanji sucks in through his nose, gathering his patience. “The exam is to test the organ that helps with your jizz. It’s not a typical checkup that our dear doctor would run. Besides, he’s handed me the reins on the crew’s nutritional intake.” He levels Zoro with a raised brow, almost blasé with how Zoro is already losing interest in the conversation. “How do I dumb it down for you: I’m in charge of food. Prostate makes jizz. You eat jizz. I check your prostate.” 

“Sounds like I’m doing all the work making it.”

Sanji cuffs Zoro on the back of the head. “ You sit there while I stretch you and milk you. How is any of that work?!”

“And you sit there while I slice up sea kings,” Zoro answers indignantly. “You don’t see me claiming I’m doing all the work for dinner.”

Sanji snorts and throws his hands up in the air. “Fine. Check your own prostate then.”

Satisfied with his victory, Zoro grins and makes himself comfortable again, leaning back at the kitchen table with his hands tucked behind his head, more smug than he has any right to be.

Sanji begins a countdown in his mind: Any second now… three… two… one…

Zoro’s brow furrows suddenly.

“Cook,” and the hesitance in his voice carries across the galley. “Where’s the prostate?”

Sanji withholds the finer details—Zoro asking aloud is enough ammunition for Sanji to convince the mosshead that he needs Sanji’s help yet again. 

As for the execution of his plan, he waits until their next island stop; Chopper’s med ward is empty, as is the rest of the ship. The crew—all except himself and Zoro, that is—are out getting their land legs and supplies, leaving him to his own devices.

“Pants and underpants off, marimo. Might as well take off your boots too.” 

A beleaguered sigh then rustling fabric is the only sign his instructions are heeded. Sanji turns his attention to his tools spread across the counter. With freshly washed hands, he dons the sanitary gloves and glances over his shoulder to check on Zoro’s progress.

His clothes are scattered; the last leg of his pants is stuck on his ankle as he’s forcing off his remaining boot. Sanji watches in amusement as Zoro hops to regain his balance, tosses the shoe, then kicks his pants across the room. His underwear follows in a similar manner; yanked down with little finesse, then left on the floor where he steps out of it.

Sanji sighs, then comforts himself with the sight of Zoro’s flaccid length; it’s lost on Zoro really, but that’s why Sanji is here. To teach the marimo what he’s good for.

At least the regular milking and stretching activities they’ve done together have Zoro less prudish about Sanji seeing his naked body—no matter how fully Zoro remembers some of them. He stands with his arms crossed and his dick out, waiting for further instruction.

“Take a seat,” Sanji directs, and before Zoro can sprawl over the examination bench, he clarifies, “right on the edge, then you can lie down.”

He rolls over to the edge of the bench on the doctor’s stool, and as Zoro gets settled, he pulls out the tucked away stirrups.

“Heels up here. Then scoot down. Your ass needs to be hanging off the bench.”

Zoro’s head shoots up from the head of the bench. “The hell kind of setup is this?!”

“A medical one,” Sanji shoots back snottily. “C’mon.”

“You still haven’t told me where the damn thing is,” Zoro grouses, face scrunching into a dirty look. “I can do it myself if you just tell me what to look for.”

“It’s not something you can do to yourself that easily,” Sanji scoffs. When Zoro doesn’t move for the stirrups, he sighs and rolls his head back to stare at the ceiling. “It’s in your ass, dipshit.”

Zoro’s expression twists. “Like under the glutes or—”

Sanji shakes his head solemnly, and color floods Zoro’s face. “You’re just gonna stare at my asshole?!” At Sanji’s impatient tap of the stirrups, Zoro begins to kick his heels up into them. “That’s weird, even for you, cook.”

“Grow up, Zoro. Do you want to know about your protein production or not? Or are you satisfied with whatever second-grade jizz you’re making?”

“My jizz is better than yours ,” Zoro retorts childishly. After a beat, he inches down the table. 

“More, Zoro,” Sanji drawls, beckoning him further down. When he’s positioned to Sanji’s liking, legs spread out of the way, ass exposed, dick soft against his stomach, Sanji retrieves the lube and warms it on his gloved fingers.

Zoro peeks up at the sound.

“Whassat?”

“Lubricant. Makes the penetration less painful.”

Sanji watches the spark begin to light in real time, tracking as Zoro’s eyes flicker between his slicked up fingers and his own crotch. 

“Wait, you’re putting that where ?!”

“Yes, Zoro. My finger is going in your asshole to check your prostate. Do you have any other objections?”

With furrowed brows and a deep pout, Zoro stares at Sanji, seemingly weighing whether the confirmation that his spunk does in fact produce the maximum amount of protein was worth Sanji sticking a digit where the sun don’t shine. At last, he seems to make his peace with it, and his head flops back on the bench with a huffy exhale.

Satisfied that he can finally begin without further interruption, Sanji wheels in close; with his dry hand, he pets down Zoro’s inner thigh until he reaches the cheeks of his ass. His thumb tugs to the side, and the pucker opens with it, just enough space for him to wiggle in a finger. As soon as his lubed fingertip circles the hole, Zoro clenches.

“Easy,” Sanji coaxes. “Don’t be nervous.”

There’s a grumbling protest above, but Sanji pays it no mind as Zoro relaxes. His finger slips in.

“Doing okay, Zoro?” He thrusts in tiny increments, nudges his finger in to the first knuckle, and then the second.

“Fine.” Zoro’s voice is tight, like he’s straining every muscle above the waist to keep from bearing down around Sanji’s intrusion.

Sanji takes him at his word and worms further in, then curls his finger lightly. Heat tightens around his finger and a punched out breath escapes Zoro. 

“ Ho ly shit,” he gasps.

Jackpot.

“Are you all right, moss?” Faux concern drips in his voice.

“Cook, fuck . What was that?”

“What was what?” He fights to keep the grin off his face, dragging his index just off to the side of Zoro’s prostate.

Zoro shifts in place, almost riding Sanji’s finger as he does, and that alone has Sanji’s nose itching to bleed. “To the,” he huffs. “Fuck, the other way.”

Sanji overcorrects. Zoro follows, hips shifting to get Sanji back on course. 

“Hold still .” 

“Right, no, my right.” 

He’s trying his best to chase the flash of pleasure Sanji teased—his cock is firming up from it. Sanji’s too, from how greedy the moss is acting. Benevolently, he drags over the spot Zoro is itching for, feels the give of the bundle of nerves even as Zoro’s rim tightens painfully around his finger.

“ Fuck —! That,” Zoro heaves in staggered breaths, “that’s good—th’ protein’s working—”

Hearing the mantra he’s been instilling within Zoro come so easily from his lips is intoxicating, especially given how foggy he can be after some of their special protein shake sessions. The moss is conflating pleasure and protein production so naturally—with this hurdle behind him, what more can Sanji convince Zoro of under the guise of building his strength?

“You think?” Sanji asks, adding a second finger and digging into the gland. Zoro’s voice cracks from the strain and his dick twitches. 

“Is it supposed to feel like this?!”

“Like what?”

“Cook,” Zoro groans, broken and shuddering. From this angle, Sanji can see his balls drawing upwards, “I think I’m gonna piss —”

“ Control yourself, Zoro. I'm trying to do my job here, don’t you dare piss all over me.”

Sanji doesn’t let up, and he smacks away Zoro’s hand before it cups over his cockhead. He feels the ring of muscle around his fingers contract and pulse before he sees ejaculate shoot up Zoro’s stomach in time with his muscles clenching and his wrecked moans.

He slips his fingers free, grazing over Zoro’s prostate once more to watch a shudder ripple through him. Before the twitching hole can draw his focus for too long, he turns to flip an hourglass.

“Well, that’s good at least,” he comments absently, returning his attention to Zoro. “You can make jizz without your dick being touched. I am a little worried though. Your prostate is on the small side.”

“Tch. Bigger than yours.”

Sanji’s pulse spikes. “You don’t know that. And it’s not .”

Zoro huffs a laugh, pleased enough with himself for getting under Sanji’s skin.

“Anyway,” Sanji continues, reaching for a vial next. “We’ll need to test how much protein is in your jizz. That’ll tell us most of what we need to know.” He scoops a dollop of semen into a vial and sets it aside, then stares expectantly at Zoro. “Well, don’t waste it.”

Zoro grunts then drags his thumb through the sticky mess on his skin then over his tongue to lick it clean. Sanji watches, his own dick throbbing in his pants at the sight. When Zoro next has his thumb tucked in his mouth to lick clean, Sanji drops a lube-slicked hand to Zoro’s softening dick and squeezes once.

“Hah?!”

“Just the next phase of the exam, Zoro,” Sanji coos. “Testing your refractory period.”

“How many fucking parts is this fucking test,” Zoro huffs, wincing from the overstimulation he’s too stubborn to complain about. “And what the hell is a factory period?

“Refractory,” Sanji corrects, thumbing over the head of Zoro’s dick. It’s still soft. Zoro’s muscles twitch beneath him. “Optimal protein production occurs when your prostate can make multiple batches of jizz in a short period of time. We’re timing how long it takes your prostate before your next round is ready.”

“There’s—you can do more than one?!”

Sanji hums in confirmation, twisting his wrist and relishing in the small bouts of suffering that flit over Zoro’s face. 

“What, can’t take it?”

“Of course, I can—!”

“It’s taking you quite a while to get hard again,” he notes scathingly. “Are you only able to produce a single batch of jizz at once? That’s not good.”

He releases Zoro’s dick, giving the poor moss some reprieve before his hole is abused more. In the interim, he begins to prepare for the next phase. 

While Zoro blusters on the bench, Sanji plucks a stainless steel plug from the table. Around the base of the toy is a wide ring, only connected by three evenly-spaced machine screws protruding from the plug and secured in place by a wingnut each. He slicks up the plug with lube; the liquid dribbles into the hollow center and the three creases where the plug is meant to separate.

“...way more jizz than you, you shitty cook,” Zoro’s grumbling when Sanji tunes back in.

“Sure, moss,” he placates. “All right. I need to take a closer look,” he says, pressing the plug against Zoro’s hole, not waiting for him to protest any further.

The lube helps it glide in smoothly, despite Zoro tensing at the sudden intrusion. Once the plug is seated inside Zoro, Sanji gets right to work on the wingnuts. He watches, eyes alight with interest as each segment of the plug separates one by one until there’s a noticeable gap between each of them, no more than a few centimeters. He glances up to see Zoro’s brow dotted with sweat, his cheeks flushed, labored breaths escaping him at odd intervals.

“You gonna make it, moss?”

Zoro grimaces, wholly unintimidating. “Shut up. This is nothing.”

Sanji shrugs and continues on with painstaking slowness. He pumps at Zoro’s dick when it begins to harden, urging him to relax before the next expansion of the plug. The hollow spaces of the toy give Sanji plenty to watch: Zoro’s rim twitches continually, unable to clench tight enough to close. The fluttering pink muscle beyond the rim is utterly entrancing. Sanji can’t help but push Zoro’s unspoken limits, eking his hole open wider with each twist of a wingnut.  

When the gap at the center of the plug is wider than Sanji’s finger, his patience snaps. It’s not quite at the fullest setting, but it is Zoro’s first time. And Sanji is eager.

With a hand on Zoro’s cock, and a finger tucked in his hole between the spaces he’s carved out for himself, he finds Zoro’s prostate immediately. Beautiful sounds escape him, deep groans that pitch high when Sanji rubs particularly meanly against the bundle of nerves and his tip at the same time.

“Go on, moss,” Sanji urges, a wicked grin splitting pain up his cheeks as Zoro’s legs twitch on either side of him, his fingers digging into the bench cushion, his hips jumping between grinding back on Sanji’s fingers and up into his fist. “Where’s all the jizz you were bragging about?”

Zoro’s moaning is unintelligible, and only moments later, he comes; a sad little load that could barely fill the indent of his belly button.

“Fucking hell, cook,” Zoro croaks, twitching from the aftermath of his second orgasm.

“There, that wasn’t so bad, was it?” Sanji goads. He doesn’t stop or slow his assault. “Is two all you can do, santoryuu ?” 

Zoro’s weight presses heavily against the stirrups and the finger lodged inside him; he’s propping himself up with one hand on the bench behind him and gripping at Sanji’s clothes with the other. 

“Fuck,” he cries out. His entire body shakes. “Fuck, cook, I—dunno if I—”

There’s a loud crack , and one of Zoro’s legs falls as the stirrups holding it aloft snaps at the joint. The sudden shift in position sends him hurtling over the edge; he sobs and pulls Sanji closer, every muscle in his body winding up as tight as possible as tremors wrack his frame.

Nothing new spills from his cock; it’s still damp from the last load that pathetically dribbled from it only minutes ago. Zoro collapses in a sweaty heap. Sanji extricates himself; he discards the lube-covered gloves and portions out the last bit of Zoro’s spunk between a new vial and Zoro’s mouth. Zoro receives the remaining jizz so passively, tongue lolling out for Sanji to drag his fingers over.

Sanji tuts, and it seems to pull Zoro from his foggy bliss.

“You only made two loads,” Sanji explains, the wheels in his mind already turning. “We’ve got a lot of work to do if that’s all the protein you can make.”

“What… do I even do … to make more?” Zoro asks weakly. He’s covered in a sheen of sweat, chest heaving as he tries to catch his breath.

He’s so glad Zoro asked.