Sherlock’s tail was a dark charcoal gray. It was long and lithe and it wrapped around things seemingly of its own volition. Sherlock used it as an additional hand, and the first time that Sherlock’s tail reached across John to pick up the cup of tea John had made for him, John actually dropped his own cup of tea, startled. It was highly unusual to have a tail that was so skillfully prehensile. John, as a doctor, had studied all of the types and knew that Sherlock’s was by far the rarest, found in a vanishingly small percentage of the population: less than one percent at last guess. It was difficult to get full statistics, of course, because people with such prehensile tails tended to downplay it, frightened that everyone else would think they were freaks. John discovered after only a very short time of living with Sherlock that Sherlock relied on his tail an astonishing amount. Later he would learn that Sherlock had not been born with such a responsive tail but had worked very hard on it, and John thought that was a typically Sherlockian combination of stubborn determination and laziness toward doing things with only two hands the way everyone else did.
For something John knew Sherlock was proud of, Sherlock took terrible care of his tail. Sherlock dragged it through mud and muck and God knew what else, letting it trail after him when it wasn’t in active use rather than properly holding it up out of the fray. He was terrible about washing it. The fur on it was short, and John thought that it would probably be smooth and gleaming if Sherlock properly washed it as frequently as it needed to be washed, and then combed it out the way it ought to have been combed out, but Sherlock couldn’t be bothered. When John had pointed it out, Sherlock had frowned over at his tail, stretched out on the floor, lashed the very tip of it in a skillful display of control, and then said, “Boring,” and turned back to his experiment.
It made little sense to John at first, because Sherlock was otherwise fastidious about his appearance, but John eventually saw that it was part of Sherlock’s love-hate relationship with his tail: He loved that it was talented, hated that the rest of the world didn’t see it as talented, and so resented it over being yet another thing that set him apart from everyone else. Sherlock’s relationship with his tail was complicated, and Sherlock pretended to hate it by ignoring it while secretly being very fond of it and using it constantly.
John’s tail was bushy and dull, a cross between a red squirrel and a fox. And John really did dislike his tail; his dislike for it was not covering up a secret bursting pride over it. He didn’t passionately hate it or anything, it was just inconvenient and not something he was fond of about himself, not, he thought, one of his better features. His tail’s fur was long and so prone to tangling, and John had no choice but to spend lots of time each day combing it out. This was possibly why Sherlock’s dismissive attitude toward his own tail frustrated John so much. Sherlock’s tail had short hair, it would have been a dream to take care of. John wished he had such a tail. Everything got caught in his tail, no matter how much John tried to keep it out of the way, and John was constantly pulling detritus out of it. Chasing after criminals didn’t help matters, and sometimes John sat picking things out of his tail in the cab on the way back to Baker Street. He would pull his tail over, across his lap, and hold it in place. Sherlock, hunched up against his door, his own tail curled up on the space between them in the seat, always watched this curiously.
“So it doesn’t stay where you put it,” he remarked one night.
John, fighting to keep the tail as much in front of him as possible while also extracting a small branch of bramble, said, “It’s supposed to be behind me, Sherlock, not in front.”
“Hmm,” said Sherlock, as if the idea were interesting to him. He lifted his own tail up, dancing it in front of his eyes. The very tip of it was black because it had been dipped in tar at some point during the chase.
John glanced over at him. “Show-off,” he muttered.
“I don’t know how you deal with having a part of your body that is so uncooperative,” remarked Sherlock.
“It’s how I developed enough patience to put up with you,” John rejoined.
Mycroft had a small deer tail, very unassuming. Deer tails were in fashion, highly coveted, and John always thought that his nose was wrinkled in slight distaste by the way John’s tail brushed in his wake, a constant, rustling presence. Because of this, John liked that Sherlock normally made a habit of holding his violin bow with his tail whenever Mycroft was around.
Mrs. Hudson’s tail was a wolf’s. John had long ago learned not to make assumptions about people’s character based on their tails, but he admitted to surprise over Mrs. Hudson’s wolf-tail. Most of the wolf-tailed people he’d met in his life had been fierce: people you didn’t cross, vicious in their defense of the things that mattered to them.
“What makes you think Mrs. Hudson isn’t vicious when crossed?” Sherlock asked, eyes closed, sprawled on the couch. He had his fingers steepled together under his chin and his tail making lazy figure-8s in the sky above him.
“Don’t read my mind like that,” said John, annoyed. But Sherlock’s comment came back to him at points throughout their acquaintance. Because Mrs. Hudson had a will of iron and John decided that he definitely would never have wished to cross her.
Lestrade had the silky tail of a golden retriever, and he was vain about it, so that it always shone like spun silk. At crime scenes it stood out like a beacon, reflecting all light, even the feeblest. And it wagged when Lestrade was pleased at something, an automatic reaction that Lestrade could not control. It didn’t seem to bother Lestrade, who John supposed was used to it, but John was relieved he didn’t have such a traitor of a tail. Sometimes Sherlock smiled at him, or stood a little too closely, or let his eyes linger impossibly on John’s lips. At those times, John thought a tail like Lestrade’s would have been wagging madly and given him entirely away.
Anderson had a thin, hairless tail, on the short side. John privately thought it resembled a rat’s tail, although shorter than most rat’s tails John had seen, but Anderson insisted it was an armadillo’s. When Anderson had told John that, Sherlock had snorted. John had let it go.
Donovan had a little bunny tail. As it was a smaller tail, it was one of the more coveted types, but she seemed self-conscious about it, as if she felt the absence behind her.
Molly had a tail like a Siberian husky. It was strikingly snow white, which must have required her constant care and attention. It curled in on itself in a way that made it seem shy, like it didn’t want to take up too much space. John actually wished his would do that, rather than curling outward in the ostentatious way that it did. Her tail did not wag the way Lestrade’s did. John wasn’t sure if Molly’s was more controllable or if the lack of wagging was rooted in an underlying personality difference. Molly did always seem to be suspended in stillness, waiting for an external cue.
Moriarty’s tail was like Sherlock’s, cat-like, although his was pitch black and John thought he had less control over it than Sherlock did his. At the pool, Sherlock’s tail was very still, curled up protectively behind him, waiting for Sherlock to decide what he needed it to do, and Sherlock didn’t use it until he’d negligently stuck the gun into it while using both of his hands to make sure John was alright. John had weakly protested the safety of the gun waving around in the air being held by a tail, and then Moriarty had come back, his tail swishing along behind him with impatient, snappish movements. Sherlock had grabbed the gun back into his hand and had used his tail as leverage to push himself up and away from John, and Moriarty, tail looking even more agitated, had stood across from him in a face-off.
And then the mobile had rung.
For months after Sherlock jumped off St. Bart’s, John could not manage to hold his tail up. It dragged along behind him and John considered the effort it would take to lift it up properly and wished there was a way to chop it off. He had learned about such experiments in med school and he had always considered it silly, like chopping off your nose because your sinuses got clogged every once in a while. But now he wished he could do it. He felt like every day his bedraggled tail reminded him of everything that he had lost. When he went to bed at night, he would clutch his tail up to his face and sob into it, and he hated that he did that. He hated everything about who he was with Sherlock gone.
Eventually, finally, he sat and groomed his tail out, and when he stood, he held it up where it was supposed to be, the effort of it no longer mountainous, and the brush of it on the back of his neck was familiar and comforting, like an old friend coming home, although not the old friend he longed for.
Sherlock came home looking bloody terrible, and John tried to be angry about it, except that, at the sight of him, his tail gave an involuntary twitch. It was the closest thing to a wag John had ever felt out of it, and he’d thought, Oh, bloody hell, after all this, really, you do still love him, don’t you?
John tried to be cautious, tried to get Sherlock to understand how hurt he had been, and Sherlock watched him with enormous eyes, with his tail still, drinking him in and saying, Yes, yes, I know, I’m sorry, like a mantra. Sherlock clearly wanted him back with a desperation that John understood, because it was the same way he’d wanted Sherlock back.
So he capitulated.
And, once they’d got back into cohabitation, it took John all of two hours to realize something. He finished making their cups of tea and walked into the sitting room and put them down on the desk and looked at Sherlock on the sofa and said, “What did you do to your tail?”
And Sherlock’s tail didn’t move. Sherlock’s tail, which once had been part of the tidal wave of motion and energy that was this man, sat next to him, limp and lifeless. John had thought it had been dragging behind Sherlock because Sherlock always had his tail dragging behind him when it wasn’t in active use, but no, clearly Sherlock had done something to his tail.
Sherlock’s eyes had been closed. He didn’t open them. He waited a moment, then he said, “I broke it.”
A broken tail was inconvenient, of course, but not unheard of. A prehensile tail might never be exactly the same after a break, but it would still basically work. It would still respond, if stiffly.
John looked at it critically, wishing Sherlock would let him do a proper examination but unsure if it would be welcomed. “A break’s not the end of the world,” he said. “Maybe you just need a bit of physical therapy.”
There was a long silence. Sherlock’s breaths were heavy. When he spoke, his words were thick like lead. “I…didn’t have time to have it set…I didn’t…I thought…And then it stopped…I can’t get it to…”
Sherlock sounded on the verge of tears, and John understood why. Because Sherlock had always loved his unusual tail despite his professed negligence toward it, and Sherlock had broken it badly and then not got it proper care, and it had failed him and would keep failing him, forever, a souvenir of a terrible time, like John’s aching shoulder.
John spoke carefully. “Sherlock. Let me look at it.”
Sherlock immediately sat up and pulled his tail up and into his lap defensively, as if John had been about to reach out and grab it. “There’s nothing you can do about it.”
“You don’t know that.”
“Broken things heal.”
“It didn’t. It didn’t do it properly. I didn’t do it properly.”
“Even things you destroy with your idiocy can be fixed to be almost as good as new.”
Sherlock looked like he was holding his breath. He looked up at John, quicksilver eyes anxious, and John was aware they were no longer talking about Sherlock’s tail. “Can they?”
“With a little help from me,” he said, gently.
Sherlock looked up at him and pressed trembling lips together, and John knew the terrifying temptation of hope, because he was hovering on the verge of it himself.
“Come on,” he said, and held out his hand.
And Sherlock took it. John led him into the bathroom, where he made him stand over the tub, and he held Sherlock’s tail and washed it, and then washed it again, and then washed it again. Sherlock said nothing, just let him do it, although his breath by the third time through was quick and shallow and John felt as if there were no air in the world.
John took a deep breath and combed Sherlock’s tail out, combed it until it was gleaming.
Sherlock’s hands were tight fists of self-control when he asked, voice low and gravelly and rough with arousal, “Is all this necessary for your examination, doctor?”
John looked up at him, at his dilated pupils, and stroked at his tail, which made Sherlock sway a little bit on his feet, and John thought that this was what happened when you neglected your tail for too long. “Your tail is like velvet,” John told him.
“It’s fur, John,” Sherlock scoffed, clearly trying to cling to practicality.
“I always knew it would be like velvet if you’d’ve let me take proper care of it.”
There was a moment of silence. “I didn’t know you wanted to.”
“Idiot,” said John, fondly.
Afterwards, when the urgency of the first orgasms were out of the way and they were sprawled naked in Sherlock’s bed, John really did give the tail a proper examination. He wrapped it experimentally around his hand, just to see, and let go. It unspiralled itself slowly, uncoiling back into straightness. Which was actually a good sign. A completely dead tail would have just dropped to the mattress in a heap.
“Well?” asked Sherlock, sounding drowsy and content, and John thought he was pleased that Sherlock didn’t even seem to care what happened to his tail, because if John couldn’t fix his tail, John wanted Sherlock to have something to make him happy, and maybe that something was him.
“It looks to me like it’s all just dulled. Like your scar tissue around it’s built up so thick that your tail can’t get past it. We’ll take you in for an X-ray, but if we could just cut the scar tissue out, you’d be almost as good as new.”
Sherlock looked up at him, and John was expecting some kind of comment about his tail, and then Sherlock said, “Lie down.”
“There’s something I’ve been wanting to try for forever,” Sherlock told him, looking very solemn. “But I don’t know if you’ll…”
John, thinking of everything they’d just done in the bathroom and then the bedroom, wondered what it could possibly be. “I’m sure it’s fine, Sherlock. What is it?”
Sherlock reached, hesitantly, toward John’s tail. John, guessing his intention, pushed it in his direction, curious as to what Sherlock would do next.
Sherlock tugged on it a bit, pulling it over to him more.
“Does it hurt?” he asked.
“No,” John said, honestly.
And then Sherlock snuggled down under John’s tail, pulling it over him like a blanket, cuddling into the russet-colored fur. “Mmm,” said Sherlock, closing his eyes. “Is this okay?”
John stared down at him, curled up under the blanket of his tail, and felt his heart so big in his chest it might choke him. “Yes. Absolutely. Completely okay.”
And Sherlock slept, and John kept his tail fanned out protectively over him, keeping him safe.