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"You can pull over here. Yes, at the bus stop," Sherlock instructed the cab driver.
John looked up from checking his emails on his phone. They had been heading back to Baker Street after the debriefing on a particularly gruesome case involving sex trafficking and a brace of badgers, but Sherlock was now telling the cabbie to halt outside an office block in deepest Soho.
"Why are we stopping, change of plans?" John enquired, glancing over at Sherlock, who was already half-raised and reaching for the door handle.
"Yes. It's nothing. Just pay the man and wait for me here," he said in an especially terse voice, and with that Sherlock strode off across the road, leaving John fumbling for his wallet. Finally locating a crumpled fiver and a handful of change in his back pocket, John settled up - the driver complaining all the while about the brief journey being hardly worth stopping for - as he tracked Sherlock weaving in and out of drunken pub-goers, then pausing at a set of ornate Victorian lanterns before heading down some stairs. Into the public conveniences, John realized with a start.
John was intimately familiar with the ins and outs of Sherlock's bowel movements. As a public schoolboy, Sherlock had a somewhat laissez-faire attitude to bathroom privacy - one that John also shared from his time in the army. Being blokes, they pissed with the door open, casual nudity was no big deal, and John was used to regularly finding well-thumbed anatomy texts balanced on the cistern after Sherlock had had a crap. He wasn't averse to taking the Sunday supplements in there himself, for that matter. And Sherlock never opened the window afterwards either, the bastard. But shitting with the door open - or talking to each other whilst having a crap - was a step beyond that neither had ever traversed. Even as flat mates and colleagues, and with Sherlock failing to observe several boundaries of common decency, there were limits.
But Sherlock was so damn controlled that it was rare to see him exhibiting these little necessities of daily human life, especially out of the privacy of the flat. And the fact that he clearly could not wait to continue his business until they'd reached the convenience of 221b worried John. Sherlock had such bad personal habits, falling to sustain himself anywhere beyond the basic requirements of what was needed to continue working. And then there was his favoring for cocaine, his little vice, which he dipped into now and then when the cases were slacking off. Since cracking the badger international prostitution ring a couple of nights ago, Sherlock had definitely been indulging himself, staying out to the wee hours the night before, and only coming home to shower and change for today's briefing. Heaven knew if he'd even eaten anything in the past twenty-four hours. In truth, John half-suspected that Sherlock was still high.
Pausing for only a moment, John followed Sherlock into the gents, nodding at the surly toilet attendant-slash-security guard as he deposited his twenty-pence entrance fee.
"Sherlock?" he called softly, as he headed deeper into the ammonia and bleach-scented space, his pupils contracting under the harsh fluorescent lights. "Sherlock, are you alright?"
"Go away!" came Sherlock's voice from one of the cubicles, muffled by the scarred and scuffed aluminum door. "Go away, John. I told you to wait by the bus stop."
"Sherlock, I'm worried about you. Did you eat something dodgy? Have you got bad guts? I could probably see if there's a Superdrug or something nearby and get you some Imodium, some of those melty quick dissolve ones-"
"John, shut up and fuck off! I'm fine. I just…need a minute." Sherlock's voice sounded weaker than usual to John's ears, even allowing for the tinny acoustics of the tiled room.
As he spoke, two lads came down the stairs, laughing idiotically at some jest. Giving John just the briefest curious look-over, they moved to the urinals and started to piss. John waited until they had given their hands a cursory wash and left before tapping gently on the toilet door.
"Sherlock look, if this is about whatever you got up to last night, well, it's not like I approve or anything, but you know I'm not going to judge you and-"
His mindless monologue was thankfully interrupted by a deep groan from within the cubical, Sherlock's usual baritone dropping even lower than normal.
"John, I am asking you for the last time. Please. Leave. I…don't want you to hear this."
"Hear what? Sherlock are you injecting now or what? Please talk to m-"
The relative silence of the bathroom was split by a shuddering groan, Sherlock's voice sounding half-pleasured, half-pained. From within the cubical walls came the rude sounds of violent diarrhea, as Sherlock voided his guts into the stainless steel bowl. John took an involuntary step backwards and turned as the stench wafted over him, wanting to give Sherlock his privacy, but also worried by the tone of his ejaculation.
"Sherlock, look, I'm going to leave you to it, but do you need anything-"
Again, he was cut off by a loud exclamation from within the stall, as Sherlock keened and shat and finished with something close to a sob. When his voice came again, several moments later, it was hazy and vague.
"John. Are you still there?"
John paused before answering, uncertain if this was a medical emergency or something else. The smell of shit pervaded the cheap aerosol fug of the bogs.
"Yes. Are you in pain? Do you need me to, you know, come in there? That sounded fairly severe."
There was a ratcheting click as the door latch was flicked open; the chain jingled and the toilet flushed. John tentatively pushed the door open with his fingertips, and Sherlock's pale and sweaty visage came into view. He was slumped on the toilet, crisp suit trousers and boxers now a crumpled pool around his ankles. Eying John's worried face, he made an effort to straighten before another cramp contracted his belly, and he bent forward with a low moan before rearing back. John watched with mounting concern, as another spasm passed through Sherlock, whose eyes teared up as he pooped and groaned and came! Spunk flecked John's nice sensible anorak, as Sherlock pulsated wildly, his enormous, handsome, slightly curved cock Catherine-wheeling as he farted the remnants of his joy into the bowl, his normally guarded face incandescent with pleasure.
Finally, as the tremors left his gently twitching form, Sherlock raised his eyes to John's, taking in his disbelieving and gob-smacked stare, and the dots of semen speckling his shoes.
"John, I need to tell you something. I have…a condition."
"Guh?" said John, intelligently.
"It's very rare. Mycroft took me to a doctor in Harvey Street when I was twelve. They concluded that, whilst my penis is gorgeous and stately and perfectly curved, my anus is…unfortunately sensitive."
He paused, uncharacteristically bashful, his amazingly reflective eyes downcast to the floor. John gulped, trying to force air into his unresponsive lungs. Finally he managed to choke out the words, "So…your bum hole is. Abnormal?" His voice rose and quivered on the last word.
"Not abnormal, John. Honestly!" Some of Sherlock’s old acerbic tone had crept back into his voice; the abstract part of John's brain that was not fixated on Sherlock's arsehole noted that this was a good sign.
"Sorry, no. Not abnormal. Just overly sensitive?"
Sherlock sighed, stretching back like a stretchy, stretchy cat. "Yes John, I have what is commonly known as Fluttering Anus Syndrome. It affects one in two-point-four million, but when it happens the sensitive nerves of the anus are directly correlating with those of the glans. Succinctly, any sort of activity in the anal region is exquisitely sensitive for me and my knob. As I'm sure you can understand, this can cause problems in daily life."
John took a moment to recollect his thoughts. "Fluttering Anus Syndrome? I think I read a paper referencing that at the Helsinki butt disorder conference in 1998. But, shit Sherlock, it must make bowel movements intensely uncomfortable for you?" John burst forth. Exuberantly.
"Not just uncomfortable, John. Christ, you saw what happened tonight! Any sort of fecal encounter turns me into a cuming machine! Which is, of course, why I try to restrict such activities to the privacy of our own bathroom. You may have wondered for my propensity for playing Radio 4 so loudly whilst I am ensconced? (John hadn't) Well, it's to drown out the sounds of my release. This naturally explains my lack of appetite and my fondness for codeine-based substances. Of course, I try and restrict my bowel movements to just twice a week, usually when you are in your clinic."
John's mind raced. Of course! It all made such sense now! And yet—
"Sherlock, this current, um, accidental unveiling of your syndrome. Does it have anything to do with last night's antics?"
Sherlock's beautiful reflective eyes shone with both pride and the light of the overhead fixtures. John couldn't help but squirm a little in his pants at the impressed expression on his face.
"I was wondering if you'd figure it out. I must admit to underestimating the purity of last night's batch, and of calculating the effects it would have on my proceedings today."
"So what you're trying to say is-"
"Yes, John. I have what is colloquially termed as the "coke shits"."
Sherlock hung his head, as if in shame at his body's failings, although John could see from the relative erectness of his magnificent penis that the syndrome had in no way completed it's ravages upon his flat mate’s lean frame. He groped for the medical professional part of his brain, the one that was not now digesting such inflammatory information, even as his eyes lingered on Sherlock's swelling cock.
"Well, as medical conditions go, I can see that it is inconvenient—"
His words were cut off by the sudden predatory gleam in Sherlock's eyes as they fixed on his own.
"Inconvenient is one term for it yes, but trust me doctor, I have learned to live with the restrictions the syndrome may place upon my digestive system. Those I can live with; food is a passing interest for me anyway. As for the secondary benefits…well, as a medical man, you can intuit for yourself."
Ignoring the reek of shit, John stepped forward, fascinated despite himself.
“So what you are trying to say Sherlock is that, well, your bum hole is really sensitive.”
Again, the gleam in those beautiful, terrifying eyes. Sherlock reached for the sliver of bog roll left on the spool, and lazily dabbed his perineum.
“Exactly, my dear Watson.”
John found his mouth moving as though disconnected from his brain, his hands groping for his wallet even as his gob formed the words.
“So, if you’re nearly done here, shall we go and flag down a cab home?”
“The game is on. Let’s just stop at the chemist first for Imodium and an enema kit.”