John had been so fiercely tired and preoccupied that he'd forgotten to change out of his uniform and lab coat from the hospital, and didn't realize it until he'd gone to unlock the door, reaching into his pocket, and - nothing. Luckily, he normally left his phone in his pocket, so he pulled it out, texting his arrogant flatmate. 'Forgot my keys, unlock the door for me.'
A set of footsteps came tumbling down the stairs, and the door was wrenched open in front of him, a critical eye looking him up and down, giving him a once over right there on the stoop. John just shook his head, pushed past Sherlock, and climbed the flight of stairs, feeling those ever-shifting eyes watching his back.
It was almost six weeks later that John got a text while at work. 'Wear your uniform home tonight. Need it for a case. SH' He sighed, and went about the rest of his day, wearing said uniform home - though he'd left his lab coat in his neatly organized locker, ready for Monday's work.
He'd gotten as far as the front door, keys in hand, when the feeling started, low in his belly. He sniffed the air, and recognized it immediately. 'An omega's been here," he thought. He shook his head to clear the scent, and unlocked the door, climbing the stairs.
The scent just got stronger as he did, and he scrambled up the last five or six stairs, bursting into the sitting room. Sherlock sat on the couch, his dressing gown hanging askew from a bare shoulder, and just looked at him, giving him the same once over as he had six weeks previously.
"John," he managed, swallowing visibly, staring at him, "come here."
John had a hard time not racing across the room, and thrusting his nose against Sherlock's neck. Instead, he reigned in his instincts, clamped down on them tightly, and walked, not ran, across the room, to sit next to his flatmate, who smelled so much like an Omega in that moment that all he wanted to do was flip the man over, tear his pajamas from his legs, and thrust into him. But, Sherlock was an Alpha, and Alpha's didn't do that to one another. Unless there was a perfectly good reason for it.
So he didn't. Just sat there, brimming with instinct, cock hard and wanting. "How come you smell of Omega, Sherlock?" he asked, wondering vaguely if he'd even get an answer.
Sherlock sat there, staring hard at him, and slowly said, "Because I am one."
He tried not to let the thoughts crossing his mind appear on his face, but he knew he was fighting a losing battle. "You're an Alpha if I've ever met one." But he couldn't stop himself, suddenly crowding into Sherlock's personal space, thrusting his nose against Sherlock's skin and inhaling.
"How? How did I not know this?" he asked, reeling back from the scent on his skin.
"Because I don't let it be known. I have no intentions on being bred or bonded. Or should say, had," Sherlock huffed a laugh. "John," he started again, "my heat is coming, and I need it to be you. It has to be you." He let John look at him looking at John, dragging his eyes up and down that lovely uniform clad body, and repeated himself. "It has to be you."
John groaned. "How long before it comes? And how have you kept it hidden for so long? I never would've known."
"Less than an hour. I take a suppressor pill, it masks my scent, and keeps my heats from coming. I know when they come, but I have another set of medications that I take to stop it," he said, carding a hand through John's fair hair. That hand dropped down to smooth over his uniform, that tightly fitting uniform, that was second skin to John, after all his years of service. "Less than a half hour. Less than fifteen minutes. Less than ten. John, less than five. Please. Less than one." He felt the quickening inside him, the surge of hormones racing through his body, felt his body shifting, and felt a sudden urge to literally pounce on top John and make him fuck him.
The scent in the air suddenly changed, and John was suddenly glad it was Friday. He pushed Sherlock roughly down, face down on the couch, and ripped his pajamas from his legs, clawing at that funny plaid dressing gown, just to get him undressed, and fingers in his arse. He started to pull at his own clothes, but Sherlock's voice stopped him. "Leave it on John. Leave it on, I want you in it when you're fucking me, want to feel it against my skin."
So, he stopped pulling at his top, and instead started pulling at his zip, the buttons, and freed his cock to the pheromone-scented air. It wagged appreciatively at Sherlock's upturned arse, which was currently being finger-fucked by John's right hand, his gun hand. "You like those fingers, Sherlock? Like them in your arse, spreading you nice and open?
Sherlock's answering moan was all he needed to remove his fingers, and line up, and just push inside Sherlock's well-lubricated body, waiting to accept him, pushed all the way in until he bottomed out. He fisted his hand in Sherlock's hair, pulling him upright, the other hand on his hip, keeping him steady. "I want you to move, Sherlock. Move up and down on my cock. You belong to me, and you'll do what I tell you. Understand?"
Sherlock whimpered from the fierceness of John's request, and began moving up and down, shaking his arse from side to side as he did it, happy to be filled, and happy to be ordered around. He slid up, almost all the way down, then slammed his hips back down forcefully, repeated the motion twice, before John couldn't take it anymore
John held him up, and just a bit off to one side, rearranging his limbs, until he could lay Sherlock completely down on the couch. He moved a pillow away from his face, and started moving again.
"Take your shirt off, John, please," he whined out, "and let me have it." John had to clear his head, before his fingers would comply. He never stopped driving into Sherlock's waiting body, just rode it out, feeling his knot forming, pushing slowly inside him. He tossed the shirt over Sherlock's head, who reached around and pulled his face to it. He rubbed his cheek against it, marking it with his scent, mixing John's dominant Alpha scent with his own, traced the patch and embroidery with his nose, and moaned loudly, and John was still driving into his body, pounding hard. "Johnnnnnnn," he moaned, "you've got to make me come. Please make me come. I want to feel you, need you, need you to make me yours."
He let out a gutteral moan, and pulled hard on Sherlock's hips, to get once hand around his hard cock, sweeping one thumb across the head of it, making his hips move in time, and pinning him there between John's cock, and John's hand.
Sherlock bit down on John's military shirt, right in the middle of his name tape, the neatly embroidered 'WATSON' between his teeth.
"Jesus, Sherlock," he started shakily, "you are just so open and accepting my cock. I wish you could see how this looks. It's amazing."
"Tell me then," Sherlock grunted, teeth clenched into the velcro of John's nametape.
"You, your pale upturned ass, my cock is driving in and out of it, it's just amazing, that you can accept so much." He gave a rough pull on Sherlock's hips, and his hand squeezed in the same moment John pushed back into him with ferocity, and Sherlock shouted, shirt still between his teeth, and came shakily onto John's shirt. The shout was enough to spurn John on, thrusting rougher and rougher into him, and his knot tightened, and as he gave one last thrust into Sherlock's body, he was caught inside, coming harder than he had ever, the scent of Sherlock's body making him writhe against him.
Sherlock's body wrung a second orgasm from John's, who stiffened against him, and when it had relaxed, although still knotted, he gingerly helped Sherlock lift himself and rotate to the side, spooning him from behind. A minute later another orgasm wracked him, and Sherlock's fingers were drifting over his side, touching his trousers, running his fingers against them lovingly.
"S-sherlock," he panted, "what made you decide this?"
He felt a huff of what sounded like laughter, and Sherlock's body tightened against him once more, keeping him still while it wrung his pleasure from him. When it relaxed, he heard a mumble, "that damnable uniform."
He was still panting at this point, but the orgasms are coming slower now, the heat releasing from him. "My uniform made you decide to bond and breed with me?"
Sherlock laughed, genuinely laughed. "No, that I had decided months ago. I just hadn't found a reason to act on it. Until you came home in it. It turned me on beyond belief, and I knew it was time."
John felt Sherlock's body release him, and his knot retreat, but he stayed inside his new lover, stroking black curls so soft. "Uniforms are kinky, then?"
Sherlock smiled. "Just yours." The fire in his belly sated for the time being. But he knew, in about four hours or so, they'd be back at it again, trying to cure the itch, quench the desire.
Over the course of the weekend, they had near continuous sex for 48 hours. When John returned to work on Monday, he was so tired, he wore his uniform home again that night, not realizing his mistake. That was when he learned - it was not a good idea to wear his uniform home unless he was prepared for several hours of the most gratifying sex in his life.
Which goes without saying, he wore it home a lot more often.