Her Majesty's Secret Service
This is a Johnlock story, but it starts pre-canon with John in Afghanistan. If you want to skip the smutty Omegaverse stuff and go straight to the part when John and Sherlock meet, go straight to Chapter 13.
John Watson was not the first Omega to serve in the army as a medic to a unit of Alpha Marines, but he gave his service a very… personal touch. Omegaverse with Omega!John. Trigger warnings for dub-con (because let's face it the whole Omegaverse is pretty dubious regarding consent issues) and for explicit m/m sexytimes because everyone loves John! I'll also add that this is my fantasy world where sex is for fun and you can't catch anything from it – in real life please practise safe sex.
The first time it happened by accident.
Lt. John Watson had already put up the "no service" sign on the door of the First Aid station, and was slowly packing everything away for his four-day leave. Not that he was going anywhere, of course. Even if Afghanistan had boasted vacation spots worth visiting he was never going to see them. "Personal leave" (which everyone knew was just a euphemism for "heat leave") did not allow him to go more than a few kilometres from the army base, and in fact he would probably spend it all in his own quarters anyway. With his favourite dildo. Not as good as being bent over and taken by a real Alpha, but the best he could manage out here in the desert.
He rather resented having to take the time off for his biological needs, but he knew it would create havoc in the unit if he tried to continue to work and offer medical care while in heat. His particular unit was a very highly trained and finely tuned network exclusively of Alpha Marines. He was very proud of their work and had no thought of disrupting their unit cohesion by his presence in heat. The last thing he wanted was to see his unit at each other's throats fighting over him. At least the leave was granted in excess of his other leave, so he was not burning up his sick leave days every time he had his heats. The Omega Anti-Discrimination laws had seen to that.
So here he was, rolling bandages and packing away IV lines in strict military order. This way if anyone else needed to access any of the equipment it would all be exactly where it should be. He had cut it rather fine this month. He could already feel himself beginning to sweat as pre-heat hormones started to flush through his body. Soon, he promised himself. Just finish sorting out the plaster trolley and then go have a lovely long shower. His shirt was starting to stick to his skin already. Definitely a shower first.
He checked the time: only 16:20. Damn, another forty minutes before he could close up completely and head back to his quarters. Would anyone mind if he knocked off early? Probably not, under the circumstances, but what if someone urgently needed a medic and he was not to be found? His replacement would not be available through the paging system until 17:00.
He sighed and started collecting the loose papers on the desk for filing. Not really his job, but he needed something to distract himself from the uncomfortable damp stickiness starting to collect under his arms and in the small of his back.
Still only 16:25 and John suddenly decided he could not stand it a moment longer. He would never desert his post, but there was nothing in the regulations about taking off his shirt early, was there? Dammit, even if there was something about "proper uniform" in the book he would be very unlucky to get caught and prosecuted in the last thirty-five minutes of his shift before a heat leave. He stripped off his shirt and sighed with relief at the cool air across his torso. Usually the heat in Afghanistan was not too much of a bother for him, except at this time of the month. He kicked off his shoes and socks as well, for good measure.
More comfortable than he had been all day, John started whistling as he put away the last few clean instruments and restocked the IV supplies. He was interrupted by a brisk military double knock at the door and the unit's assistant medic poked his head around the door frame.
"John, if you haven't left yet, Tony just wanted a…" Bill trailed off as he caught sight and scent of John. Half-naked, sweating John already flushed with heat hormones. Bill closed his mouth and swallowed audibly.
John turned and looked over his shoulder. "Sorry Bill, I didn't catch that. What does Tony need? Not another bloody hangover cure. Tell him this is the last time and next time I expect him to buy his own bloody paracetamol." John caught up a box out the trolley he was sorting and pitched it underhand to Bill where he was standing in the doorway. It bounced off his chest as Bill made no move to catch it.
"Hey, Bill." John frowned and started to make his way across the room. "What's the matter? Are you OK?"
"Oh God, John." Bill suddenly put up both hands in a warding-off motion. "Do you know what you look like, what you smell like? You should have requested urgent relief for your heat leave."
John shrugged. "It's only another half an hour. It'll be fine."
Bill stepped fully into the First Aid station, closing the door behind himself and leaning against it. "What will be fine, John? You might be fine, but what about me?" He looked at the ceiling and licked his lips. "You smell pretty damn fine, John. When are you off duty, say again?"
John sidled uneasily a bit further away from Bill, who was still avoiding his eyes. "I'm off in another twenty minutes, actually. But if you are suggesting… helping me through this heat, I'm not sure that's a good idea. Might be a problem for unit cohesion if it became known that we were…"
"We could be…" Bill suddenly locked his eyes on John's and started prowling across the room, never letting his gaze waver. John felt a chill in his gut. This was no longer his friend and colleague in the room, this was an aroused Alpha who was stalking him.
"Bill! Bill, think of the unit! This is me, John, your drinking buddy, your mate…" Too late, John realized his unfortunate choice of words had turned a delicate situation into a disaster.
"My mate, yes…" hissed Bill, and sprang.
All the Alphas of the unit were bigger and stronger than John. They were all soldiers trained in hand to hand combat, but Bill topped him by twenty centimetres and thirty kilos of pure muscle. Before John could blink twice he was pinned against the desk. This could only end one way.
John shrugged internally and let his Omega-self rise to the surface. If this was going to happen, he might as well enjoy it. He hadn't been royally buggered for a long time, and if Bill's crushing arms around him were any indication this was going to be an excitingly rough shag.
John tilted his head forward to allow Bill to scent the nape of his neck, and to signal his submission. He felt the imprisoning embrace relax slightly as the message was received, and Bill's nips along his shoulder and neck softened into gentler bites and kisses. The hard pressure of an Alpha cock into his lower back was no less urgent though.
"Let me just slip these off, love." John whispered over his shoulder, as he quickly unfastened his belt and trousers. In one smooth move he slid everything off the lower half of his body, giving thanks that he was already barefoot. In this mood Bill was likely to rip his fatigues right off him and that would require difficult explanations when he requisitioned a new pair.
In less than a second after he was naked Bill was plastered all over his back again. Bill's hands wandering down his front to tease his nipples and stroke his little Omega cock. Bill was crooning in his ear, "Does that feel good, John? I'm going to make you so happy, John. Tell me you want me to make it good for you…"
John rolled his eyes a little, knowing that Bill couldn't see. Even in the middle of a heat-driven crazed sexual encounter the good old Alpha ego always needed a little stroking. Still, the stroking that Bill was giving him in return was putting John in a very good mood, and his heat was rising fast now to match the eagerness of the Alpha behind him. Bill's pheromones and bites were causing John's hormones to tip into full heat sooner than he might have if he had been alone in his room. It was lucky John had already removed his trousers or they would be hopelessly soaked with the natural lubricant which was already pouring out of him. Actually, Bill's trousers were getting very wet but he did not seem to be bothered by it.
"Yes, love, I'm so wet for you," John replied, "Feel how eager I am for you. I want you inside me, filling me, taking me." He wriggled his hips against Bill and felt a thrust in return.
"Right here, John? Are you ready for me to take you right now? Please let me take you right now." Bill was tugging at his belt with one hand but was unable to work the buckle without taking his other hand off John's cock. Obviously he had no intention of doing that. Finally he just yanked the belt and the buckle gave way, then Bill was shoving down his trousers.
John did a quick scan around the room. He had no particular objection to being taken over the desk, but there was an examination bed only a few metres away which would be a lot more comfortable. He decided to try for it. Worst case scenario they might end up on the floor half-way between.
"Bill? Honey? This desk is a bit sharp against my hips." John put a little whine into his voice. "If you want me to enjoy it more, maybe the bed?"
Bill growled and grasping John by the hips, turned and lifted him bodily and carried him across the room to the bed. He dropped John on his back and stood over him looking down for a moment, while John struggled to regain the breath that had been knocked out of him as he landed.
Then there was no time to breathe, or even to think. Bill was all over him biting, licking, sucking. His hands were teasing and stroking until John was overwhelmed by a sensual tornado. All he was aware of was that he was still empty, his desperate longing to be filled yet unsatisfied.
John finally managed to focus enough to gasp out, "Take me now! Fill me with your Alpha cock, I need it!" He pulled his knees up and apart, exposing his slick entrance and was immediately rewarded with the sensation of Bill's erection prodding at him. John took a deep breath and allowed his knees to sag apart as widely as possible and with a smooth thrust of his pelvis Bill slid deeply into him. They both groaned as they fitted together, perfectly matched. John wrapped his legs around Bill's waist and pulled him deeper into his body, even as Bill slid his hands behind John's shoulders to press their chests together. John bit down on Bill's shoulder to encourage him and Bill bucked his hips in response.
"Oh God, yes, just like that," panted John as every thrust of Bill's cock pushed deeply against his sweet spot. It was perfection and John abandoned himself to the mounting waves of hot pleasure washing over his whole body. It was glorious and John wanted it to go on forever, even while he could feel the spectacular ending rapidly approaching.
Bill was growling deep in his chest and the vibrations through John's body were turning him on so much he could hardly stand it. Then Bill reached down into the narrow sweaty space between their bodies and pumped John's shaft firmly up and down the entire length and John was screaming and spurting all over both of them. His internal muscles clamped down on Bill's cock with rapid tight pulses and Bill was groaning and filling John with his seed. He collapsed on top of John even as his knot inflated, binding them together and creating a delightful pressure against John's internal walls. They held and stroked one another as their breathing slowed and they relaxed together in a satisfied, sweaty pile.
Just then the door slammed open and two Alpha marines burst in shouting, "John! John are you all right? We heard you screaming!" Captain Spiers and Lt. Wright gave one horrified glance at the scene of debauchery in front of them and started trying to wrench Bill off John.
"Ow! Wait!" yelled John. "We're knotted together, just give us a minute willya? I'm fine, it's all fine." John winked at them over Bill's shoulder. "More than fine, actually. My heat has started and Bill was just helping me."
Captain Spiers' eyes widened and his nostrils flared as he scented John's heat pheromones and the smell of sweat and semen in the small room.
"I'm off-duty now, you know." John added in a smaller voice. "You don't think this will be bad for the unit, do you Captain? There won't be any jealousy because of this?" John frowned anxiously.
The Captain nuzzled John's neck and kissed his way along John's jaw to his mouth. He kissed John and thoroughly explored his mouth before replying, "I don't see why anyone should be jealous when there is plenty of you to go around."