Alrighty, I am not sure HOW I have missed this, but there's a thing called the omegaverse. Haven't heard of it? You will!

The world consists of males and females, but also three subclass genders; Alpha, beta, omega. Betas are the most common, and are regular people like you or me basically, but alphas and omegas are rare. The omegas, no matter if it's a male or female, will go into heat regularly and during that time, they can easily get pregnant. Alphas respond to the phermones that omegas in heat send out, which causes the alpha to go into heat as well, they go into a rut. If you want more details on this, I suggest you google it, it's pretty lewd and pretty awesome imo. Anyhow, let's get started on some smut shall we!

There hadn't been a lot of times in his life that Hatake Kakashi had used a service like this one, a brothel where you for a pretty high penny get to rut with an omega in heat. For some reason as he passed through the village just outside of Konoha on his was back from a mission, when he had seen the bright neon signs outside and around the door, he had decided to enter.

Curiosity was mostly to blame, but also a need to sate his lust and ease the symptoms of his rut which was making it increasingly difficult to focus.

It was now late summer, and a common time for omegas to go into heat, a natural adaptation in order to have babies just when spring came around, and even if omegas were technically rare he had encountered several omegas in heat during this mission, causing his own libido to go into overdrive. Naturally they had several more heats a year, but during this period they had more intense heats, and some even said that the omegas were more fertile during the last summer heat than during the rest of the year.

Kakashi had known since he was young that he was an alpha, and he had rutted with many betas and a few omegas through the years, but none so far this year, and when he saw the brothel that offered this kind of service, and catching a whiff of the smell of delicious omegas in heat inside the building, he decided to let his instincts have their way with him.

The owner of the place recognized him as a shinobi from the hidden leaf, and greeted him as an old friend even though they had never met. He gave Kakashi two choices, either he could meet one omega in private for the duration of their heat for a higher fee, or for a slightly smaller fee he join the 'dark room' where several omegas and several alphas were together for a number of days, joining and rutting until the heat ended. Watching others breed omegas, and getting the chance to rut with more than one omega sounded very good to Kakashi, so he choose that option.

After paying the owner up front, he was asked to remove his weapons, a rule which he could understand and respect, so he removed his vest and his gear without any protest and handed them over to the owner who locked all of it into a small safe and handled Kakashi a key on a chain to hang around his neck. Kakashi was already feeling his body responding to the pheromones of the omegas, and he was itching to get into the room and be able to sate his lust, he could feel himself getting restless.

The owner smiled, recognizing the look of frustration, need and lust on his new customer, and after a brief explanation that there would be food provided in a joint room, he opened up the door to one of the several dark room sections inside the building. The silver haired man entered without hesitation, and the owner closed the door again.

Kakashi paused inside when the door closed, letting his eye adapt to the darkness. The moment he had entered the room, the smell and pheromones of omegas in heat had hit him like a wall, and his dick had become instantly rock hard. The room wasn't completely dark, it was lit up by some blue and red lights here and there, there was two rooms to the right that seemed to be completely dark, and Kakashi could hear the sound of flesh slapping together with flesh, and loud moans and groans from there. Noticing some shelves with clothes and other items right next to him, he decided that getting naked as soon as possible would be a great idea, and stripped in a hurry. He could feel his body responding to the omega heat, he was already in heat himself and he needed to mount and breed someone, he needed it to the point where nothing else soon would matter at all.

Finally completely naked, he entered the first room that looked to be completely dark, and barely through the door someone grabbed his arm. In a lot of situations he might have had a very shinobi like reaction to that, but one deep whiff of the air coming from the other person told him exactly what he wanted to know – this was an omega. Before he knew what he was going he had pushed the other against the wall and claimed their mouth in a hard kiss, it was a male omega he noticed, but that was fine, he didn't mind, in particularly not right now. His hands found their way around the male squirming under his ministrations, noticing that this male was slim, but muscular and fit. He roughly kneaded the firm ass cheeks while he pressed his body against the other, his hard dick already flowing with pre-cum, rubbing it into the belly of his partner-to-be. When his hands found their way to the puckered entrance of his play mate, he shivered in pleasure when feeling that no other alpha had rutted with this omega so far in this heat, something that pleased his instincts more than he would have thought.

The omega in his arms were moaning, his hands pulling on Kakashi's hair, his body pressing back against Kakashi's in need, his hips moving in circles against the alpha. It was more than Kakashi could handle at the moment, and he let his hips sink lower while he hooked his hands under the ass of the omega, so that when he came back up he had lifted the other male and placed him against the wall, and his cock was sliding along the crotch of the male in front of him, rubbing it back and forward a few times while spreading the butt cheeks apart with his hands. He was panting hard, his heart was racing, and all he could think about is how he would soon sink his cock into this delicious body.

"Please..." it was a hushed whisper against his ear, and he groaned. He wasn't the only one loosing his mind to the heat, and by judging on the slick that had coated his cock he wasn't the only one more than ready to begin the rut. With no further delay he lined his cock up with the twitching entrance and pushed inside with a slow and steady thrust, feeling the man tense and arch his back, for a second or two he wanted to ask if his partner was ok, but the wet heat and the pulsing feeling inside was too addicting already, and he needed more, much more. His hips started thrusting erratically, almost by their own will, and soon he was thrusting in hard into his omega playmate, burying himself hard and deep inside.

"Ah, ah, ahh, oh god, oh gooood..." The omega was mewling in joy, and Kakashi felt pleased by this. He started licking the omega under the ear and down his neck, finding there a wide collar to protect the omega from being bitten on the neck by, and thus bonded too, any alpha that would mount him in here. Kakashi bit down on the collar itself and tugged on it, while curving his body more, thrusting in harder, feeling the omega claw on his back and thrust back against his hips in wanton.

By now the sound of their flesh hitting each other was loud in the room, together with their moans, mewls and groaning. He pushed the omega hard against the wall, the legs of the smaller male wrapping around him, guiding him into that delicious body, over and over. Kakashi couldn't get over the feeling that he needed more, much more, and giving a small growl while holding onto the slim hips of his partner he put all his effort into getting deeper, thrusting harder, really trying his best to sate his instincts to breed this omega in heat.

He could already feel his knot start to form, in all the previous times when he had rutted, he had never once felt the need to knot his partner, if anything that posed as a dangerous risk for him as a shinobi, but this time was different. He wanted, no he NEEDED, to get his knot inside this omega. The feeling of his knot being just too small to bond, but still much larger than his cock, and to thrust that in and out of the omega, it was enough to make his eyes roll back in his head from the pleasure.

He was panting hard, as was his partner, and then his knot were the size where he had to choose if he wanted it on the outside, or stuck on the inside, and all his instincts screamed at him to thrust it deep inside, and he agreed with that instinct. With a chest deep growl he pushed his hips forward as hard as he could, hearing the omega in his arm hiccup and twitch in surprise as the large knot was pushed into him. Kakashi kept pushing it deeper and deeper, letting it swell up to its final size, locking him together with the omega. Feeling that tight channel pulse and convulse in pleasure around his knot made him see stars flashing before his eyes, and the feeling of the omega coming, spraying his cum between their bodies while rocking himself on Kakashi's cock was the last thing he needed. He could feel his cock start spewing out come into the omega, his body trying its best to put a baby into his partner.

Both men was panting hard, and Kakashi let himself sink down to the floor, still connected and bond to the omega in his arms. They were both drenched in sweat and trying to catch their breath, but he didn't mind.

"I have to say...that was really intense." He could feel the omega tense up in his arms the moment he spoke the words, and his mind became more alert. The omega was holding his breath for a few seconds, and then tentatively seemed to try and decide on something.

"...Kakashi san?" He too tensed up in his body when he heard that voice now that his mind had calmed from getting to sate his instincts. His cock was still pulsing out cum inside the omega, and his body was still twitching from the pleasure, but he had to confirm what his gut already knew.

"...Iruka sensei?"

Umino Iruka had known since he was a teen that he was an omega. While it was rare to be born an omega, he hadn't celebrated this discovery. He knew from a young age that it may make other shinobi look at him like he was weaker, inferior, and sometimes even a freak show.

Then there was alphas. Many alphas became shinobi, because they were naturally more muscular, had more testosterone, and were good at taking leadership roles. For years Iruka had struggled not to show his status as an omega, he had struggled not to be tempted by the strong alpha pheromones, he kept it hidden the best he could, fearing how the other shinobi would treat him differently if they knew.

He took heat suppressants and told himself that he would only accept a partner if that person fell in love with him before knowing his omega gender. He dreamed of finding a good partner, the normal way, and to have a long and healthy relationship full of love and a bunch of children.

Sadly the years went on, and while he did have a few relationships, none of them became the permanent one he had dreamed about, he couldn't find the romantic partner he had wished for.

As he was closing in on middle age, a high age in the eyes of shinobi, he began to realize that if he waited much longer, he may not be able to have a family at all, and just like that, it was like he had come to a cross-road in life.

This in combination of him over hearing some males speaking about an omega brothel outside of Konoha gave him an idea. It was a crazy idea, but it appealed to him.

He could go there when he had his heat, and let an alpha breed with him, but without taking the birth control pills. If he did that, he'd almost be certain to get pregnant, and while he would miss out on getting the romantic partner he wished for, he would at least get to have a child before he grew too old for it, and having been in contact with children for every day for many years now, his wish to have a child of his own was getting desperate.

His instinct as an omega was to get pregnant, his body, heart and mind all yearned for it.

He waited until the last heat of the summer, when omegas are rumored to be extra fertile, since he didn't want to have to do something like this more than once in order to get a baby, and then he went to the rumored brothel outside of Konoha. He had talked to the owner before hand, and the man seemed to understand omegas well, so well that he didn't mind letting Iruka use his service to get pregnant – as long as he paid the same amount as the alphas did to enter.

Iruka had been shocked by this, but he knew, as did the owner, that his need was strong enough to accept that offer, and he paid up. He had never been so nervous about something in his whole life, but he was also excited for it. He would finally have a child of his own, all he had to do was let an alpha breed with him during his heat.

His heart had hammered loudly in his chest when he had entered the dark rooms naked except a sturdy leather collar around the neck. He knew what would happen if an alpha bit him during their rut, they would be tied together for the rest of their life as mates, so in a way he felt very grateful for the owner that had let him use one of the collars, since he didn't own one of his own.

The smell of other omegas in heat inside the dark room was a strange experience, but it also made his own that much stronger, he was stiff and nervous, expecting strange alphas to throw themselves at him from every direction, but as he stood there he realized that there must already be an even number of alphas and omegas inside this unit, because everyone he could sense seemed already to be rutting with a partner.

He rubbed a hand over his face, and went into one of the dark rooms to the side. There didn't seem to be anyone else in there, so he took a few deep breaths and tried to calm down. This was his first time really allowing himself to feel his heat, to live it out completely without any type of suppressants, and it felt weird. He was leaking slick from his ass, his body was shivering and tingeing as his skin was releasing pheromones to try and call an alpha to him. It felt a bit like he was having a fever, and his mind was a bit foggy, his body a bit slow and he was constantly a little out of breath.

In his mind it was like he had a really bad craving for something that he couldn't really figure out what it was, but his need for it was increasing for the minute, and it didn't take long before he was stroking his cock while listing to the other people mating, one hand slipping behind to his hole, letting his fingers slide up and down the cleft, imagining what would soon happen.

While this stimuli did get him very excited, no matter how he did it, it wasn't enough. He was getting really frustrated with all these strange emotions when he noticed that the door to the dark room unit was opened, if the light coming into this smaller room for a few seconds were anything to judge by. He froze, and focused his senses. He could hear someone moving around outside, but he wasn't sure if he should go there, wait here, or what he should do, so he just didn't move. A few minutes after a person was standing in the door, just a few meters away from him, and his mind went crazy. This man was an alpha, there was no doubt about it, and he was flooding his surrounding with his alpha pheromones, almost enough to make Iruka moan.

Iruka reached out, and was able to find a strong wrist in the almost completely dark room. He could feel the alpha focus on him, and he froze, uncertain what he should do now. Turns out he didn't have to do a thing, in a swift movement the alpha had thrown him up against the wall behind him, and claimed his mouth in a fierce kiss. His mind went haywire. His senses exploded from the taste of this alpha. His body shook, his ass twitched, and he let out a moan. Feeling the strong body of this alpha male thrusting itself against him, handling him like a doll, and then lifting him up like he was nothing, it all turned him on so bad. When he felt the hard cock of this alpha male rub against his entrance and his cleft, his desperation was peaking.

"Please..." He did and didn't know what he was begging for, he just needed something, and he needed it now. When his prayer was answered and the hard cock entered him, his breath caught in the back of his throat, and when that cock started moving, he could not hold back his moans. Fireworks were going off inside of him, knowing that this was a strong healthy alpha who were mating with him, that he was finally after all these years, going to get to feel what all the other omegas had been obsessing about. Every time the alpha thrust inside of Iruka, it felt like Iruka had an orgasm. With every single thrust it felt like a thousand fireworks blasted off, it was so intense, he had never felt such pleasure before.

"Ah, ah, ahh, oh god, oh gooood..." His moans poured out from his mouth in a steady stream, and he gasped when he felt the alpha start licking his neck, every nerve in his skin there seemed to be set on fire. When the alpha started to bite and pull on his collar he groaned, it was a possessive move from the alpha and he let out a deep growl while doing it. It was displaying that he would have liked to bite Iruka, to mark him as his own, and it brought out a primal pleasure from deep inside on the brunette, playing on his deep fantasies about a romantic partner.

He could dimly register the increasing excitement of the alpha soon after that, he noticed how the thrusts became harder and more desperate. His body craved what the man had to give, his legs held the alpha against his body, not letting the other male pull out completely, and his hands were holding onto a pair of broad and strong shoulders. He was urging the male to thrust deep and hard, rolling his hips on instinct with the trust from the other male.

Iruka wasn't mentally prepared for the knot though, although he knew that alphas had them, he also knew that not all alphas would use it, most of them not even in heat. First he thought the alpha was just pleasuring himself with the growing knot, but then when it was almost too large to push into Iruka, the male had thrust forward hard, pushing it in, and kept pushing, letting it swell and lock inside of Iruka. The increased pressure, and knowing that this meant that this male would almost certainly be the one to father his child, it made Iruka come hard, his whole body convulsing and spasming, his cock spraying out a large load of cum between him and the alpha, coating them both with it. And then, barely back to his senses after his hard orgasm, the alpha started to come inside of him. He gasped, his insides tingled and he could feel himself being stretched from both the knot and the huge load that was being pumped into him. With this much, his pregnancy was almost completely guaranteed, and Iruka shivered and held onto the alpha that was breeding him. The alpha sat down, with Iruka on his lap, still knotted together, both of them panting hard.

"I have to say...that was really intense." When he heard that voice, and actually recognized it, he froze. No, that couldn't be it. But he knew, he was certain. His mind was panicking wildly inside of his head, but he couldn't help but to try and confirm it.

"...Kakashi-san?" When he felt the alpha under him tense up at that name, he knew for sure that he hadn't been mistaken. He could still feel the man coming inside of him, filling him up with more and more cum, steadily increasing Iruka's chances of getting pregnant.

"...Iruka sensei?"

He swallowed hard. He had planned to return to the village, and have his pregnancy but not tell anyone where or how he got pregnant, the alpha who planted their seeds in him would never know the mating had borne fruit, but now the very person he was going to use for that purpose is one of the few he would not be able to keep the truth hidden from. In the middle of his panic though, Iruka had to confess to himself in a small voice that he was thrilled that right now inside of him a child sired by the famous Hatake Kakashi was being made.

TBC.