A/N: Another oddly empty day before the second semester starts to write something I've been mulling over for a while. I know there are a ton of first-kiss fics out there, but I wanted to do my own spin on the genre. I also wanted to try my hand on fluff - not something I really do, as I like to keep them in-character - and on an explicit broship - as I have always liked leaving their relationship exquisitely ambiguous.

Here's to hoping I manage both.

The cover image is not mine. It's something I googled and latched onto because it's cute. Found it on weregret dot com, unattributed.

Cheers and I hope you enjoy!

(Additional Notes: This fic has been retitled a few times. Sorry, I just can't quite really settle on one. Anyway. Finally, I'm sticking with Kiss/Kill for the wordplay, the binarism - albeit lopsided - and the allusion to our favorite ex-assassin's name. Also, made some minor tweaks to the ending. So there.)

- x -

KISS/KILL

The first time they kissed, Killua was not sure how to feel. There was a surge like electricity that ran through him, but electricity was a sensation so familiar to him that he wasn't sure how to interpret it other than as a stimulus that his body automatically resisted.

The kiss had happened in the best of conditions. It was his 16th birthday. He and Gon had taken a train to the largest chocolate patisserie in the world, where he had gorged himself on sweets and pastries for hours, spending all his savings and half of Gon's. In the subsequent sugar rush, they tore across the city in the sparring race they often played, where any use of nen, except Killua's Godspeed, was allowed, whether to speed up one's own movement or to sabotage the other's. As always, it was a draw when they reached their destination: the peak of a sizable hill at the center of the forest shrouding the city's borders.

For hours, they lay on the grass in silence, broken only by Gon's periodic whispers.

"Killua...you're happy, right?"

"Mm..."

"I know it's your birthday, but I'm happy too. To be here...like this... Killua..."

"Mm?"

"You're happy...with me?"

The sugar crash took its toll. At sunset, he awoke to Gon's eyes, molten gold in the fading light, gazing at him, rapt, with an emotion he could not define. There was something else in the look that seemed to tug at him, but before he could ask anything, Gon was an inch from his face, and there was a second of frozen confusion – Gon's steady eyes locking him into place – a catch of breath that lasted a lifetime, before the raven-haired enhancer moved, slowly, carefully, and ever so slightly –

And there it was.

The first kiss.

And Killua Zoldyck was completely lost.

Gon, on the other hand, seemed absolutely certain. He lingered in the initial contact, his lips light and soft over Killua's, before gradually pressing, probing more deeply, as if easing the ex-assassin gently into the moment with him. His movements were deliberate and exact, but at the same time, hopelessly enamored. It struck Killua how naturally Gon knew how to kiss him, and how naturally his body seemed to respond – as if it answered more to Gon than it did to him.

It was like using Whirlwind, all his responses bypassing his senses – except it wasn't.

The tenderness was foreign to him. He had never known tenderness all his life.

Here, now, it did nothing but confuse him.

All he could do was nullify the involuntary jolts of electricity that seemed to surge through him repeatedly at Gon's touch – the way he always did.

It was when Gon's right hand had traced his left and had teased it out from where he had been leaning on it behind his head in his sleep, to pin it – at first gently, then more aggressively – to the ground beside his head, that Killua began to make better sense of things. Gon's fingers tangled with his, and the kisses grew more insistent, rapidly giving into the propulsion of a new and undiscovered passion.

Killua knew that hunger in Gon, had seen it often enough in the challenges they often encountered together – that excitement, that thrill, that savage want.

It was always beautiful when Gon betrayed himself.

And now Killua felt absolutely unworthy that Gon should be betraying himself to him when his body seemed to understand so little of what it meant.

Still, as Gon pushed more deeply, more aggressively, into him, his other hand finally pulling at Killua's free hand to slam it violently into the ground, Killua began to feel more at ease. Violence was his comfort zone. Violence was his safety. His body, which recognized only battle, seemed to swing into gear. That was how he recognized, in the split second it took for Gon to pin him down completely, that his best friend had lost some control over his own enhancement nen, and he immediately concentrated ten in his hand in to avoid breaking his fingers.

Thrilled to latch onto a sensation he understood, Killua moved to try more responses, but Gon reacted quickly to neutralize any motion. He buried himself in the sensation of his best friend, disarmed by his own desire yet completely in control of everything.

The energy surged between them.

Killua's body pulsed with nen now, reacting just enough so that Gon's own raging, barely contained nen did not crush him. The currents ran through him: the agony he had so long learned to bear, the ecstasy he had only just begun to explore. He made no motion to free himself but relished the clarity that came with finally being able to frame the confusion of pleasure with the familiarity of pain.

They were the same, after all.

When the kiss was done, Gon pulled back, his eyes not quite registering the cracks in the ground where he had pressed his best friend a little too roughly. He gazed at Killua, silently, for a long time, unanswered questions dangling in his eyes.

The sun sank in the horizon.

The ex-assassin sat up and massaged his wrists, experimentally. Really, enhancement is dangerous left unchecked...

His tongue moved to wet his suddenly-dry lips, and it was only then that he realized that a little of Gon still remained in them, and that it tasted a little like chocolate. He tamped down a sense of regret that he wasn't able to recognize it earlier and instead ventured the first words to break the silence.

"I...hope I didn't electrocute you by accident."

Gon laughed. "Iie. It was nothing."

A pause.

The silver of moonlight began to bleed through the shadows of early evening.

"Ne, Killua..."

"Hm?"

"I could kill them, you know..."

"What? Who are you talking about?"

Gon's eyes pierced his, the fierce gold now shadowed by evening into murky brown. "Your family. I would kill them, one by one."

Killua gaped at him, wide-eyed. What now? What happened? He gave Gon a few seconds of pregnant silence to retract his words, but the enhancer was not kidding. Killua sighed. "Okay, first of all, I'd rather not see you die trying. Second..." He threw up his hands. "Why? They're not coming after us anymore."

Gon shook his head. "If you...if you never know pleasure just because...they..." He trailed off, his fists clenched.

The raw and vulnerable desire - frustration, love - in Gon was painful to watch.

Killua took a moment to understand.

...just because they had taken away your capacity to feel pain, and, by consequence, your capacity to feel pleasure.

Indeed, what is pleasure without pain?

In answer, Killua finally did use Godspeed. In a flicker of electricity, he was by Gon's side. Another surge, and his arms were wrapped around his best friend's shoulders in a powerful embrace, a movement he had never in his life done before, but which his body seemed to find natural just then.

Yup. It was official. His body responded more to Gon than it did to him.

Taking in Gon's warm scent of wood and grass – so familiar from all the times they had slept beside each other, but now intensified by the lingering, belated sensation of their first kiss – Killua muttered, "Baka." You're the only pleasure I have ever known, Gon. Give a guy a little time to learn.

He wasn't sure if he said it out loud, but when he pulled away, Gon was smiling again. That bright smile that eclipsed the brightest sunlight.

"Gomen ne, Killua," he said, hand moving up to scratch his head in that classic way of his. "I think I stole your birthday. I'm happier than you are."

Killua smirked and thumped him on the head. "That's right!" he said, vehemently. "So you owe me dinner at the patisserie."

"What?!" Gon yelped. "Again?! But – but I'm almost broke – "

"It's not my fault you don't have savings."

"What! You're the one who doesn't keep savings – "

"Aha! So you do have savings! Pity you'd rather spend it on yourself than your best friend's ultimate happiness on his birthday..."

"But I thought the ultimate happiness was – " Gon cut himself off in time not to subject the both of them into an awkward situation. Killua, who knew fully well what the rest of the sentence would have been judging by the vivid pink that rose to his pale cheeks, gaped at him, openly flustered. Gon looked a little sheepish, but the hopeful glint in his eyes betrayed how much he meant what he had said. He shrugged, helplessly.

Killua huffed and looked away, furiously.

"Baka," he said. Then, grudgingly – "Dinner's on me."

Gon's grin stretched from ear to ear. "Yatta!"

And as he followed Gon's ecstatic bounce back to the glittering city, Killua suppressed the urge to lick his lips again.

Really. Killing is sooo much easier...

- end -

A/N: So what do you think? Did that make sense? It's a theory I've had ever since I realized how used Killua is to pain, considering his choice of nen ability. Also because I watched Lars von Trier's Nymphomaniac and it made explicit the inextricable relationship between pain and pleasure.

On a separate note, if you guys liked this and have time for more reading, do check out my other fics. Pretty please. I could use some exchanges of ideas, especially on Untouchable. I actually wrote this fic because I'm taking a break from writing that one's chapter 5.

Otherwise, thanks for reading and hope to read your thoughts on this when you leave a review! Haha. Wink wink. Cheerio.