Hiya guys. Damn, I can't believe I'm uploading this but, oh well. I know I swore to never write a yaoi story but my BFF gave me an offer I can't refuse. She asked me to make her a Yaoi story between Leo and Raph and in return she'll do a month worth of homework for me. Its too good of an offer to turn down so I wrote this as the first chapter.

For those that never know about me, well, Welcome and just Ignore the above paragraph. This takes place in A/B/O (Alpha/Beta/Omega) Universe. For those still new to this, I have a small explanation about how this world works.

I might have some typos since I think I'm gonna throw up if I re-read this. So, enjoy.

WARNING: YAOI, SMUT, FOUL LANGUAGE ETC.

Well, there they go again, fucking like there's no tomorrow. Okay, maybe more like Raph was riding Leo's cock like no tomorrow. Unlike Raph who's still full of energy, Leo was struggling to stay awake which his tired body doesn't approve that much, no matter how good it felt having Raph wrapped around his manhood (or turtlehood).The two eldest had exchanged nothing but grunts and groans for the last hour inside the pheromone filled room. Heat pheromone. Raph's heat doesn't came very often and thus, is rather unpredictable.

This time, Leo wasn't so lucky.

The blue clad turtle had just finished his training when Raph ambushed him on his way to his room. Unlike his brothers, Leo doesn't train until the training is over. Oh no, Leo trains until he's completely drained, which is usually two hours after the training is over. He was so tired that he completely missed the heat pheromone Raph had been broadcasting all over the lair. Being the only Alpha in the family, he's supposed to be the one that affected the most by this. But right now, he's too tired to even get a shower and just went straight to his room.

He was walking absentmindedly and before he know it, he was pulled by the shell into his hot head brother's room.

"C'mon, fearless, yer gettin' real sloppy." Raph said as he also felt Leo's movement – or lack of thereof. "If yer tryin' to make me beg like other Omegas, it ain't gonna work." He might be saying it, but the idea is very appealing if that's going to make Leo take his heat more seriously.

"S-sorry Raph." It was all he could get out of his mouth before he groaned again. 'Still the good ol Raph, still being the Dominant one even though he's the Omega.' Leo thought. He might be the Alpha but he's still need to fight for dominance since Raph is not very keen on being the Submissive one. Leo doesn't really mind but due to his instincts, he craved the dominant position. Right now though, he's too tired to do it.

Raph picked up speed making the alpha and the omega groaned in pleasure. "Listen, Leo. This ain't mean I'm gonna be your submissive Omega, ya hear?"

Leo just let out a weak chuckle. He knows that line all too well as Raph always said it everytime they had sex, even on their first one. 'Our first…' the memories of their first time together played back in his mind as clear as a summer day.

Two years ago…

Leonardo's P.o.V

I stood at the entrance of our Lair as I watched my two youngest brothers and my father left for their work. After saving the world for the umpteenth time, mutants are now allowed to walk freely – as long as we wore appropriate clothes - and finally treated like another human being.

We even had gotten our own jobs.

Sensei now teach the art of ninjutsu at a dojo he owned from the time before he got mutated. Mikey now works as a chef just like how he always dreamed of. There are still mysteries around the mutagen so Donnie – along with Leatherhead – was employed by the government as two of four lead scientists of the mutagen research team. Raph is now a member of NYPD which had somehow – and thankfully – soften some of his violent behaviors.

As for me, I'm proud to see myself as a firefighter of the New York Fire Department. Being a turtle really helped being a firefighter. Being cold-blooded, having a shell and thick skin grants me better resistance to fire and heat than most of the other firefighters, even the mutant ones. With that, I'm usually deployed to save those that were trapped inside the building as my fellow firefighters try to contain the fire from the outside.

It's not like they don't want to help, being a ninja makes me faster than any of them so they would only slow me down, not that I would admit it out loud. They have also seen that I was capable of the job so they never asked.

The latest fire rescue could've gone better though.

Long story short, it ended with my left hand broken and covered in minor cuts. At least I did saved more than a few lives out there. So here I am, not even able to get out of the lair.

Why are we still living in the underground lair? There are a few reasons as to why but the major one is that this had been out home for 19 years. It just doesn't feel right to leave it. It's funny how all of us had wanted to get out and move to a better place years ago when we were not allowed to even peek out to the outside world but after we're allowed to, all we could think about is what a stupid idea it is to move out.

I sighed after my brothers and sensei is out of my line of sight. I'm now alone. I turned around and went back inside, making my way to my room. On my way there, I first passed Donnie's room, then Raph's. I would've just keep walking but I was stopped abruptly when I smelled something coming out of my immediate younger brother.

Holy shit, that smell.

I almost chocked on my own saliva when I smelled it. The scent of an Omega in heat.

What the hell?

Why is there an Omega in heat inside the lair? I'm pretty sure the only Omegas in the Hamato clan are Mikey and April but Mikey had gone to work and this smell is definitely not April's. Shit. Did Raph brought an Omega inside the lair?

That's what I thought until I realized the scent is somehow … familiar. This Omega that reeks of heat pheromones smelled like motor oil and gunpowder. Wait a minute, could it be?

No. There's no way Raph's an Omega. I mean, he's a hot head with a short temper. He's brash, rude, doesn't like to lose and most of the time, without a tact. He has all the personality of a wild Alpha. Everyone I know has the Secondary Gender in sync with their personality so Raph is definitely an Alpha … right?

Just like how father is a beta because he's wise and is a great mentor. People might think master Splinter is a leader type but he's not. He taught me everything about being a leader but he's not the leader type.

Or even just like Mikey and Donnie. Donatello is calm – and a bit of a pacifist – who thinks logically so it's obvious he's also a beta. Then Mikey who's wild tendencies and easy-going personality. While he keep breaking the rules, he's always obedient when I ordered him to do something, making it obvious he's an Omega.

The Secondary Genders had never been a problem for me before.

Alpha, Beta and Omega.

Alpha is ranked the highest out of the three. All Alphas, myself included, have a need to dominate others, especially Omegas. We are either natural born Leader or a salvage Fighter. That's why Sensei choose me as the leader as soon as I was presented as an Alpha when I was 12 years old. Alphas occasionally went into Rut. It causes an Alpha to have a higher sex needs and increase in virility. Going through one without an Omega is the worst feeling an Alpha could experience. Good thing is, I'm already used to go through it without having sex.

Next is Beta. They are held in high regard and is the most common type to hold a high position in organizations or the government. It is due to Beta is the only type that is not driven by pheromone. Without them to cloud their mind judgment, a Beta is the first choice in making logical decisions.

Last is Omega. They are the "bottoms", to say crudely, in a relationship. According to sensei, long ago, Omegas are considered nothing but sex slaves. They are abused and there is no law to defend them as they were treated as nothing but property. Now though, they are the most protected type. Just having sex with an underage Omega – even if it was requested by said Omega – can be used to get someone behind the bars. Just like how Alphas have rut, Omegas have Heat which will cause an Omega to have a high sex drive and fertility. Omegas, either female or male, could get pregnant.

Alpha in rut will have be much more dominant while Omega in heat will me more submissive.

There are also other ways to determine if one is an Alpha, Beta or an Omega.

An Alpha cock is slightly swollen on the base which is called a Knot. It was used to get an Alpha to be tied with their partner during sex. For Omega, they produced Slick from their ass when aroused that works as a natural lubricant. An Alpha in rut will have bigger knot while an Omega in heat will produce more slick.

Pheromones that produced while in heat or rut works almost like a call of distress. It could go as far as to make someone lose their mind. Just like right now, my iron will is crumbling slowly.

This is bad. I can't think of anything but to rush inside and fuck whoever it is inside of Raphael's room. I could feel my growing arousal and I'm pretty sure I'm also sending back rows and rows of signal of an aroused Alpha.

"L-Leo?" A voice – Raph's voice – came out from the room. His voice is a little hoarse … and needy. Oh shit. Raph is an Omega.

Ever so slowly, I opened the door only to find myself tackled to the ground by the bigger but shorter turtle. I winced at the pain as he was on top of my broken left arm. "Ra-?" Before I could even say his name, he smacked his lips to mine. My eyes widened in shock. As soon as the shock fade, I relaxed and kissed him back, ignoring the pain. The kiss went on for a good few minutes without any of us breaking out for air. I love being a turtle.

As much as I wanted this to last forever, it can't. Eventually, we need to breathe. As we broke the kiss, we began panting like a dog in a hot day, staring at each other's eyes. As soon as I regained what little sanity I had left, I spoke. "Raph, we can't do this here."

He nodded in understanding. "Ok. Let's get to your room. My hammock is not an ideal place to have sex." He said. We got up and walked to my room. I realized my turtlehood had found its way out during our long kiss, making me blush harder. I opened the door to my room and let Raph went inside first before I followed.

Once inside, I locked the door. Turning around, my lips once again met his. He wrapped his arms around my neck. In response, I wrapped my good arm around his hips. We toppled down to my bed with me on top of him now. Grinding our cocks against each other, we continued our kiss. This time, I broke our kiss, earning a whine from Raph that doesn't sounds like him at all.

I went down to his crotch level to take a good look on his cock. It was quite big, only slightly smaller than mine and that's saying something since Alphas always had large manhood. Mine is around 11 inches while his is probably 10.

I wrapped my hand around the base of his cock and jerked it slowly. Raph groaned in pleasure and that would be the signal. I took his cock into my mouth and start sucking on in as he groaned even louder than before. His pre-cum taste slightly salty, but good.

I kept sucking on his cock while my hand jerks off the part that I couldn't fit into my mouth faster and faster until I felt his hand stopped my head from moving. I looked up to see his face, much redder than before, panting hard. "L-Leo, p-please. I-I need you inside me."

I just nodded and took his cock from my mouth. It came out with an audible "pop". I went down even lower to where his hole is. Just as I though, the hole is now drenched in his slick. I don't know what came over me but I started licking his hole without even commanding my body to do so.

"Ah, Leo, d-don't stop, agh." A groan erupted from his mouth as my tongue danced around his slick hole, trying to breach inside. As I did this, my hand found its way back to his cock and I started jerking it. However, just a few strokes later, he caught my hand. I looked up to him in surprise. "Leo, stop. I want to cum with you inside of me, please."

I smiled as he let go of my hand. My hand traveled down, prodding on his hole. It's time to prep him. I slid one finger inside quite easily due to the slick he's producing. The second finger too a little bit more time. It's understandable. This is the first time his hole was stretched like this. Raph had admitted it that he never used sex toys or more than one finger during his heats.

After determining that he's ready, I went up to kiss him while I guided my cock to Raph's entrance. Pulling out from the kiss, I stared at my younger brother. "Are you sure you want to do this, Raph?"

He nodded slowly and that's all I needed to see. I smacked my lips to his as my cock slides inside of his virgin hole. Groans and grunts is erupting from the two of us muffled by each other's presence. I keep sliding in, inch by inch, slowly but surely until my whole length – save the knot - is buried deep within him. Slowly, I pulled out until it's only the tip of my cock was inside before slamming back inside.

I picked up pace while never breaking the kiss. It was a bit awkward at first but we found a rhythm before too long. I slide in and out of him, feeling like I'm in the top of the universe. This is so much better than having to use my own hand to relieve myself, so so much that I don't think I would even came from it anymore.

Well, unfortunately, all good things have to come to an end.

As I was nearing my climax, I fuck him faster than ever before. We broke the kiss as we groaned loudly. "L-L-Leo, please k-knot me." I heard Raph said but it barely reached my ears. Of course, whether he said it or not, I will knot him. A few thrust later, he came, shooting his seed to his own and my plastron. When he came, his hole clenched around my cock and that was the last straw.

I closed my eyes and slammed my hips as hard as I could and force the swollen base of my cock inside his hole. It slides in. The knot is a success. As soon as my knot is inside, I shot my load into him, filling him with my hot seed.

I opened my eyes to look at his beautiful face. Using my hand to cup his cheeks, we shared one last kiss. It was a very short one, only for a few seconds but is no less passionate. I'm now tied to him. It took around 15 minutes before the swell on my knot died down and finally allowed me to take my cock out of his hole.

I fell to bed beside him, but before we fell asleep he said those words. "Listen, Leo. This ain't mean I'm gonna be your submissive Omega, ya hear?"

"Wouldn't dream of it, Raph."