So this just... sort of happened.
Summary: As the Watson-Morstan wedding approaches, an unresolved issue demands to make itself known. Genderflipped everyone. Shameless PWP.
My first foray into smut-writing territory, so reviews and concrit greatly appreciated.
It happens after a case. Doesn't everything?
The early hours of the morning, Sherlock is flying down back alleys and side streets, guided by the distant floods of lamp light and the pounding footsteps of her suspect. Adrenaline is coursing through her system, every nerve ending alight with the thrill of the chase and the heady knowledge that Joan is pelting along beside her, eyes glinting in the semi-darkness with an exhilaration that Sherlock is gleefully sure Mark Morstan has never inspired.
Up ahead, Sherlock spies the coat tails of her target disappearing round a corner into what she knows is a dead end. She smirks to herself, gotcha, and spurs herself on, outstripping Joan and hurtling towards the alleyway.
She doesn't bother to slow down as she barrels round the corner and zeroes in on the now stationary figure. Doesn't register until far too late the gleaming blade that emerges from the same figure's coat.
Her instincts kick in at the very last moment, time enough only for her to twist to the side. The blade swings along a perfectly executed arc and slices across her forearm, dropping Sherlock to her knees with an alarmed cry. Her hand presses to the wound, feeling her coat sleeve start to dampen with blood and hearing a distant yell of "Sherlock!" Then there is a gun shot, another shout of pain, and footsteps running towards her.
"Sherlock!" Joan repeats, dropping to her knees beside the detective. Sherlock glances over her shoulder to see her assailant sprawled unconscious at the entrance to the alley, blood pooling from a bullet wound to his shoulder. Joan is talking frantically on her mobile, demanding that the person on the other end – Lestrade, Sherlock presumes – gets their arse down here with an ambulance right now. The moment she ends the call her attention is back to Sherlock.
"Let me see that." she demands, taking Sherlock's injured arm.
"Superficial." Sherlock tells her. It really is, it will barely require stitches, certainly unworthy of the panic on Joan's face. Sherlock twitches her arm away and rises gracefully to her feet, "Really, Joan, don't make such a fuss, I'm not going to bleed out in time it takes the ambulance to arrive. I would have thought–" her diatribe is cut abruptly short as the palm of Joan's hand connects sharply with the side of her face. Her head jerks around, ears ringing from the unexpected force of the slap. She looks back around, startled, to find Joan's eyes glinting with rage and her fists clenched.
"What the bloody hell did you think you were doing?" she snarls at Sherlock, "This guy murdered three people and you decide it's a good idea to go charging straight at him without stopping to think? Godammit, Sherlock, you could've gotten yourself killed!"
For a split second Sherlock can only gape at her, struck dumb by Joan's sudden change in demeanour. After a moment she finds her voice and replies, "Highly unlikely. I knew you were right behind me after all. I have excellent faith in your skill as a doctor, Joan."
She's not sure whether she means it sincerely or jokingly, but her statement only enrages the shorter woman further. "What if it hadn't been a knife? What if he'd pulled a gun and shot you in the head, Sherlock, what the hell would you expect me to do then?"
"Joan." Sherlock is aware how fast this is sliding into Not Good territory, but before she can attempt to intervene, she's cut off.
"What if I wasn't here?" Joan almost yells. "What if one day I'm not around to stop you getting yourself murdered? Jesus Christ, Sherlock, I'm getting married, do you know what that means? It means I won't be able to prioritise your reckless arse any more, what if something happens to you while I'm not around?"
The soldier's words cut through Sherlock deeper than any blade ever could. Suddenly viciously angry, she straightens to her full height and doesn't stop the words from spilling out of her mouth. "Well, seeing as you'll be the one abandoning me, Mrs. Morstan, I fail to see how my safety will soon be any of your business."
The world seems to go quiet as Joan bristles with rage in front of her. She wavers slightly where she stands, as though oscillating between screaming again or storming off. When she lunges forward, Sherlock braces herself for another blow.
Instead she is kissed.
Joan's lips crash into Sherlock's with an urgent intensity, her hands grabbing roughly at her lapels. Warning lights flash in Sherlock's head even as she finds herself melting into Joan's arms, eyes fluttering closed.
Mrs. Morstan, her brain shrieks at her, getting married, but her body refuses to listen. Her arms circle around the older woman's waist and pull her in closer as a firm tongue invades her mouth and teeth bite down gracelessly on her bottom lip. It's rough and ragged, and just the wrong side of painful, but Sherlock knows she's couldn't have told Joan to stop if the sky was falling in on them. Not when the thought that had carried her through all her lonely nights on the run was of the slant of her ex-flatmates smile, the way the sunlight glinted off her cropped hair. Not when the though of Mark Morstan's hands, caressing and holding her, had driven Sherlock nearly wild with a feeling she was too scared to examine. As calloused hands skimmed down her back and moulded her arse in ways that should be illegal, all the warning lights in Sherlock's head are drowned out by the insistent thrumming of Joan, Joan, Joan.
A moan escapes Sherlock's lips, and she brings her hands up to fist in Joan's sandy hair, twisting and tugging. The shorter woman growls and shoves Sherlock back against the dusty brick wall, ducking her head and biting down on Sherlock's neck. The detective lets her head fall backwards, revelling in the sensations of teeth and tongue and the throbbing ache amassing between her thighs. Gripping Joan's shoulders, she shoves a knee between Joan's legs, feeling an answering jerk of her hips.
"Joan." she gasped, feeling every point of contact exploding like fireworks under her skin.
"Shut up." Joan growls, forcing a hand up under the younger woman's shirt and seizing one of her breasts through her bra. Sherlock's breath staccatos in her chest as Joan's nails dig into her flesh, sending spikes of pleasure-pain washing through her. "You're a sodding idiot."
"And you're astoundingly ruthless." Sherlock replies, before running a hand down Joan's stomach and sliding roughly between her thighs. A moan escapes the blonde's lips and Sherlock feels a thrill of triumph course through her. She untangles her other hand from Joan's hair and tugs at her belt buckle, feeling a tightening of hands on her waist.
Sherlock wasn't an idiot. She knew exactly what these few moments meant, and was determined to take all of what little Joan was willing to offer her. So she makes short work of her fly and pushes a hand into her jeans, finding her already hot and slick. Joan's mouth finds hers once more and for a long moment they're locked in a messy, scorching kiss, full of battling tongues and urgent need. Sherlock's fingers fumble inside Joan before settling into a rhythm, stroking the soldier teasingly.
Joan nips demandingly at Sherlock's jaw, growling, "Harder, dammit." Sherlock had always known she was powerless against that commanding tone. She pushes her fingers up forcefully against Joan, who whimpers in response and thrusts her hips into Sherlock's hand. The younger woman feels every cant of her hips echoed in her core, her skin burning where Joan is licking her was across her shoulder, shoving her scarf roughly out of the way. Sherlock bites her lip, clamping down the repeated utterances of Joan's name that threaten to force their way up her throat. The woman herself is panting and breathless, hips stuttering and nails digging into Sherlock's back though her coat. Sherlock feels pressure beginning to gather inside her, as though she were the core of a nuclear reactor, intense sensations that short out the rational, logical part of her brain and brings all her focus crashing down to lips and teeth and skin and Joan.
Suddenly, the blonde cries out, muscles tightening around Sherlock's fingers and head falling forward onto Sherlock's shoulder. Giving in to temptation, Sherlock slings an arm around her shoulders and holds her close, running a hand through her sweat-slicked hair. Ignoring the ache still radiating from her centre, Sherlock supports Joan as she trembles and gasps through the final waves of her orgasm, relishing the feeling of a pliant Joan Watson in her arms.
It last barely moments. Before Sherlock's addled brain can properly register what is happening Joan has pulled out of Sherlock's grasp and dropped to her knees on the litter-strewn ground.
"Joan." the detective gasps out, suddenly finding it very hard to breathe, "Joan, what–" the next moment she is abruptly cut off as, in one deft movement, Joan's hands push her skirt up around her waist, drag down her tights and underwear, and she dives forward, licking a broad stripe up Sherlock's silky folds. Sherlock lets slip a startled yelp, then melts backwards, bracing her hands on the wall behind her as Joan begins a merciless assault on her opening, holding her still with steady hands on her hips. Sherlock's normally razor-sharp intellect is quickly reduced to a broiling mass of white noise and Oh God yes. She's seen Joan take charge before, she's seen Joan be commanding and forceful, but this...
Sherlock knows it will not take her long, and soon she a tidal wave of sensation comes crashing over her, every nerve ending in her body firing off at once and her mind spiralling into the last realms of insensibility, clinging only to the sight of Joan's name, burning behind her eyelids.
For a few precious moments, she is able to simply let herself drift along on the aftershocks, eyes closed, listening to her and Joan's laboured breathing. Then suddenly, lights are flashing a street or two away and voicing are filling the air. The ambulance. Lestrade.
Sherlock's eyes snap open, only to find she is alone. Joan is all ready off down the alleyway, jeans re-buckled, calling out Lestrade's name. Just like that, the bubble is burst. Reality comes rushing back in, and Sherlock realises the full force of what just happened. She straightens herself out just in time for the murder team to arrive, escapes from the ministrations of the ambulance crew as soon as possible (it's a minor flesh wound, for God's sakes, why must everyone kick up such a fuss?) and only has to glance around the scene once to confirm what she had all ready suspected: Joan Watson is long gone.
Sherlock doesn't see her again until three days later, when she and Mark arrive at Baker Street to continue wedding plans. Neither woman can look the other in the eye, and Sherlock feels the cracks across her heart – the ones she feels more strongly every time Joan leaves her at her door and goes home to her fiancée – deepen just a little bit more.