It had gotten to the point where anyone else might label this an obsession. Atem, of course, wouldn't use such harsh wording. Then again, no one really needed to know about what was going on inside his mind except him. Kaiba would be privy to it eventually, but for now that was unimportant.

As with most obsessions it seemed to start out so innocently. Innocently enough, in fact, that he hadn't even realized he was so drawn to it. Maybe then he would have been able to nip this in the bud right when it had begun. That would have been the best solution, instead of resorting to something so entirely embarrassing. Kaiba would never let him live it down, of this he was so sure. None of it mattered after a certain point. The breaking point of things to come- and that was when he'd have to divulge everything to the brunet. The point would come where he just couldn't take it anymore; it was approaching quickly.

He tried to think retrospectively. He wanted to figure out the exact date this had begun. That was out of his reach, so instead he settled for lesser events that seemed so mundane at the time. That was where it had all started.

Days in the office- lazy days, for him, anyway. Kaiba was not one that could be labeled with words like lazy. When Atem didn't have any major tournaments to attend to, had nothing to do, didn't feel like dueling on the streets, he was often found on the couch in Kaiba's office. At first it had been reading things off of Kaiba's bookshelves. When those became glaringly annoying and analytical to his eyes (which took only a few minutes upon first thought) he resorted to bringing his own books.

He would bring puzzle books. Word games, number games, riddles; any of it was absolutely eaten up by Atem. They were good for keeping his attention when he otherwise would just lie on Kaiba's couch and not do anything.

That was except… for listening to Kaiba.

Kaiba's office could be counted as quiet by any normal person. The CEO and his rival were hardly that.

It wasn't that he was actively listening to the man. The other never did anything truly interesting for him to listen to. Soft click-clacking of his keyboard when he was working, soft rustling of papers, delicate sips of coffee. These were the normal. But it was during busier seasons that Atem would count his 'obsession' has having truly started. The days where Kaiba was so preoccupied that he'd stop being inward about his working. He'd stop remembering that Atem had slipped into the office.

He'd think aloud. Murmur. First it was plans about what he needed to do. But soon Atem found his favorite thing to listen Kaiba whisper were numbers. Endless lines of codes and accounting that Kaiba did himself. He'd softly say random numbers (random to Atem, anyway) while he was working. Sometimes he'd look up, blue eyes glazed with distant thought as the gears in his brain ground away. Atem wouldn't be able to help peering from the top of his puzzle book just to watch. It was only simple fascination. Nothing harmful.

Atem hadn't realized how accustomed he'd become to listening to Kaiba's thoughtful reprieves until there came a time he had to do without them. That time came during a painfully long overseas tournament. He'd call Kaiba once a night just to check in, tell the brunet the rankings (not that Kaiba needed him to since he watched the scores like a hawk) and then … nothing. They'd sit in silence as keystrokes sounded over the phone and soon Atem found himself drifting.

It was in those moments that Kaiba caught on, not entirely, but just a little. He thought his presence had become so mainstay in Atem's life that the other couldn't do well without it. Of course the thought was enough to encourage a smirk and a swell of his ego. His rival couldn't do without him. How beautiful.

In a more gracious mood during the next tournament far away, he had Atem take a laptop with him. This was more dangerous than either of them realized. The laptop was of a simple, but sturdy, design. It wasn't the machine that was necessarily important, but what was inside the machine. A camera equipped with a microphone. From that night on, whenever Atem had do go to a tournament far away, or Kaiba had a business trip, they'd open communications at night (particularly when Atem was about to go to bed as sleep mattered much less to Kaiba).

The cameras would come on, and they'd chat about nothing important in particular. This was by no means meant for romantic scheming. Both men didn't have enough wit in them to even dare trying to be so cheesy. They really just sat opposite each other on the screens and resumed as if they were both in the office still. Soft keystrokes, sips of coffee, shuffling of paper- and then came the most beautiful sound Atem remembered in the year prior.

The numbers.

Where he'd been drifting to sleep that night, he was suddenly alert, lying in bed, and watching the screen carefully. Kaiba wasn't looking at him, but at a different computer- murmuring.

"San, roku, nijuu, zero, zero, ichi, san, hachi,"

The numbers didn't make sense to Atem, but they didn't have to. Atem didn't care what Kaiba was working on. He just cared about how that voice suddenly sounded like the most sensual thing he'd ever remembered hearing in his entire life. As Kaiba continued counting underneath his breath, Atem leaned closer to the screen.

He realized then that it wasn't just the numbers. Kaiba was entirely focused on his work- he always was. But while the numbers were being spoken, those blue eyes were intent in such a dizzying way. His focus was so beautiful, Atem wasn't sure he could take it.

And then-

"Ah-" The noise leaked from Atem before he even realized or had a chance to stop himself.

It was more than enough to get Kaiba's attention snapping towards the other screen. Already then Atem had pushed the computer away.

"What are you doing?" The CEO asked, wary of what was going on.

"Nothing." Atem said quickly, trying to catch himself. Had he really been so focused on Kaiba's focus that he'd not realized? He'd moaned. It was embarrassing. He had much more control than this. How could this be happening to him?

"Atem." Kaiba said in warning.

The computer was turned back to him, oblivious of the red on his face. "I'm going to bed. I'll call tomorrow." With that the communications were severed.

It left Kaiba in a painfully confused spot. He wasn't even sure what that noise had been, good or bad. It certainly would be usual behavior if Atem was getting sick to want to hide it. For a moment he entertained the idea of calling back but he knew Atem wouldn't return it. With a sigh and a shake of his head he went back to work. He'd have to tuck this peculiar incident in the back of his mind for later.

Neither of them revisited it for another long couple of months. It was too many, in Atem's opinion. But he just couldn't risk losing control like that again. It made life difficult. Even when he'd come home from dueling he tried to stay away from the office. It made for restless nights and painful afternoons.

Eventually he couldn't take it anymore. He just couldn't. This one little thing had blossomed out of control and he couldn't live daily life anymore without just going to hear it one last time. So this time, he decided, he was going to do something to put a stop to it. He couldn't do this again.

Not after he was sure it was going to be an embarrassment. Kaiba would never let him live it down, but he was going to endure. And then never speak about it again.

Blue eyes met crimson as Atem's hands came down on Kaiba's desk.

"I'm busy." Kaiba said simply. He didn't have time for that intent look Atem was giving him, much as he would have liked to.

"I know." Atem replied. Oh yes, he had purposefully picked a rush hour of business. A time when Kaiba was sure to be neck deep in accounting reports. He needed him to be.

"What is it you want?" Why not cut right to the chase, Kaiba was hoping.

With no words left for an explanation he reached forward to grab the CEO's tie and pull him into a bruising kiss. Even when busy, Kaiba would never fail to rise to a challenge, especially one that was backed with claim. He'd never let Atem get that far, which was in the duelist's plan. Things would get heated and angry and eventually Kaiba would circle the desk to either press Atem to it or toss him on the couch.

That was stopped as quickly as possible. Atem rounded the desk instead which confused Kaiba, but not enough for him to stop. He then sat in the CEO's lap, something Kaiba found he liked almost a little too much. Even in a higher position, Atem wasn't giving up the ground. Atem was still beneath him somehow, but he couldn't put his finger on exactly how that was.

In the middle of groping, shedding clothing (only on Atem's part as usual) and bite marks, Atem's head came to lay on Kaiba's shoulder. He was already panting and drifting away from his original goal. He forced himself to pay attention.

His hands clutched at Kaiba's shirt. "I need…"

Kaiba smirked. "Was this part of your game?"

"Seto I need something from you." He said woefully. His pride was already smarting.

This was enough of a red flag for Kaiba's hands to still. "Using sex for favors? That's too poor of a game for you to play." He was angry, but hopeful that he was wrong. A rare occurrence.

Atem's eyes closed tightly and he willed himself to say just the bare amount. "Keep working."

"What?" It was a hiss as he forcibly pulled Atem to look at him. This was all too weird and he didn't understand it. That alone made him furious.

Atem's hands dropped to Kaiba's belt, pulling it open. He looked at Kaiba, his face redder than it had ever been in his life. "Fuck me while working. You can keep your focus, can't you?" He posed it differently. He had to.

The CEO bristled but only slightly. He saw this for what it was- the challenge anyway. The other part was bizarre. "Why would I do that?"

"So you can't manage it then." This was getting desperate but he had to keep on. With that he tried to shift off the CEO's lap.

Kaiba wasn't having it, hands digging into the smaller man's hips, hard enough to leave bruise marks. A low growl was uttered. "Don't test me."

Atem resumed unbuttoning Kaiba's pants, an almost relieved smirk on his face. "If you can't stand up to it just tell me. I know I'm a handful for you."

"Never." Kaiba hissed.

And just like that Atem was briefly touching upon something he felt he suddenly needed to survive. Just this once, though. He had to keep that in mind. He lost his breath, head falling to Kaiba's shoulders as the brunet prepared him. It wasn't enough yet, though.

The crowning moment came when he lowered himself on Seto's cock, seated himself fully on the CEO's lap. And before he even moved once after-

"…Zero, roku, hn…juu, go…"

Atem could barely contain himself. Which was good news as the faster the smaller man moved the harder it was to focus on numbers. Kaiba would never admit this but it was just simple truth. Atem's body trumped working. Usually he made a practice not to let this happen to often but here it was just blinding fact.

"Seto." He positively groaned that name.

It was the first time Kaiba had ever heard him use such a tone, even counting all the times they'd had sex before. It excited him for unknown reasons. That something as mundane to him could drive Atem up a wall. He had the upper hand in a battle that he previously never knew existed.

His arms wrapped tightly around Seto's neck and he found himself grinding shamefully against the other, trying to take as much of him in as possible as quick as possible. But he tried to still his own breathing and his moaning so that he could listen to Seto recite those beautiful numbers. It eventually became too much, without a control on himself and with Kaiba trying to actually focus on work despite what was going on, he couldn't take it.

Unlike all the other times, though, when his orgasm hit he bit his lip hard enough to draw blood to keep himself quiet. He just wanted to hear Seto go on. He just wanted to listen as he breathed heavily on the man's shoulder. How long Kaiba came after that was beyond him.

To his delight, Kaiba carried on as if this was some game he really had to win- either that or he wanted Atem a puddle of mush on his lap. Or maybe he really just was working hard. Atem didn't know and he really didn't care. Still with Kaiba inside him he shuddered, shivered and writhed as the brunet whispered numbers and even wound his arms around the other to work at his keyboard.

After a few moments Kaiba chose to speak his mind on the matter only once. "You've given me a dangerous weapon."

It was all that needed to be said.