AN: This story takes place before 'SiB', but it has spoilers for Series 2. Read no further, ye who art avoiding them!
For a prompt at the Sherlock BBC Kink Meme: Sherlock doesn't have to learn to coordinate with John during the handcuffed!fugitives chase-because John thought of this ages ago. They've already undergone learn-to-coordinate training, in handcuffs, in the flat.
Coordination
"Sherlock, I've been thinking-"
"Always good to hear about you trying new things," Sherlock said, and John resisted, with great effort, the impulse to add to the rapidly darkening bruise on Sherlock's brow.
"-That now that we are doing the consulting work properly-"
"I've been doing it properly for ages, I iinvented/i it-"
"-it might be in our best interests to do some training!" John finished.
Sherlock raised an eyebrow in contempt, then winced slightly and moved the cold pack back onto his forehead.
"Look, you didn't pick up the violin for the first time and bow out a perfect rendition of a violin concerto, and they didn't stick me in surgery on my first day at university. Think, if we had practiced jumping over fences with our hands zip tied behind our backs, you might not have fell over and brained yourself of the edge of a garbage bin."
"You want to run about with our hands tied for no reason?"
"Wouldn't it be better to cultivate a talent for it before it's needed? Learn to do something before our lives depend on it?"
Sherlock considered it, and then nodded. "Perhaps some code words, as well. To be able to coordinate things without alerting anyone else nearby."
"Right! Makes sense, doesn't it? I was thinking-"
"I'll arrange the different scenarios, and start preparing an index of code. Surprisingly good idea for your first foray into thinking, John. Bravo," Sherlock said, then tossed the cold pack into a corner and starting thumbing manically through a file of old cases.
John paused, wondering briefly if he had made a rather horrible mistake, but a glance at Sherlock's face reassured him. He could handle anything the greatest mind in London tossed his way, if it would protect them in the future. Anything.
John had to admit, when Sherlock pursued an idea he didn't do it half-arsed. The next few weeks were certainly a learning experience, although John still couldn't fathom how they could possibly get into some of the scenarios Sherlock had them run through. However, it was certainly pleasing to know he could break out of the boot of a car, blindfolded and handcuffed, while sinking slowly underwater, even if he didn't particularly want to repeat the experience.
Besides the exercises in what John had started calling 'extreme consulting', Sherlock had followed through on his promise of an index of code words, which he had hand-bound and presented to John two days after John had proposed the idea. It was roughly the same size and weight of his medical dictionary.
"This is impressive, if a bit, er, over enthusiastic," John said, flipping through a section which had different code words for each degree to turn one's head.
Sherlock scoffed. "No point in creating a code if it is not thorough."
It certainly was thorough, and if John managed to learn one code word a day, he wouldn't finish before he died of old age. And if their training was any indication, it was looking very doubtful that either of them were going to live past 50.
"There is no possible way that you know what all of these words mean," John insisted. Sherlock smirked, and motioned at the book. John turned to a random page.
"Fine, 'Jupiter Branch'," John said, picking the first phrase he saw.
"While fighting, fake left and jab right," Sherlock replied, promptly.
Unwilling to be so easily impressed, John turned to another page.
"Right then, 'Slate Poppy'."
"Run to the right 45 paces."
"'Marquee Shank'," John tried again.
"Turn 20 degrees to the left and kick."
"This is ridiculous! How could you possibly know every single phrase in this book?"
"I did create the code, and I made it very basic so that someone of your intellect level could follow along. Naturally, I mastered it in moments."
"I don't think there is anything natural about you, Sherlock. I guess I'll start studying then," John said, moving towards his chair.
"Do that later," Sherlock insisted, grabbing his arm with one hand and plucking the volume out of John's hand with the other, then tossing it away. "I want to practice setting you on fire."
So, life at Baker St now consisted of bizarre cases, and even stranger training in their down time. The odd looks they earned from the officers at the Yard, usually from Sherlock quizzing John on code words at crime scenes, increased greatly, but John was more than proud to note that injuries and life threatening situations had decreased dramatically.
And when John woke one morning to find Sherlock sprawled next to him on his bed, John's left hand cuffed to Sherlock's right, well, it was not actually all that alarming. John's arm was bent at an awkward angle, his hand resting on Sherlock's chest while Sherlock continued to rapidly text someone on his mobile.
"Picking the locks on handcuffs with our non-dominate hands?" John asked, rubbing his eyes, and pulling Sherlock's arm over with the movement, forcing him to drop his phone.
Sherlock tugged their wrists back over to him, and resumed texting.
"Perhaps later, but it occurred to me there might be an occasion where we do not have time to pick the locks, and would need move cuffed. That is the agenda today," Sherlock said.
"Excellent. This could not have waited until after I was up? How am I supposed to get dressed?"
"We'll be staying in the flat today. Once we are coordinated enough, then we'll practice outside," Sherlock said, scoffing at what ever reply he had received from his texting.
John plucked the mobile from Sherlock's hands, and tugged on their wrists until they were both standing. Then he proceeded to lead them out of the room.
"Where are we going?" Sherlock asked, frowning.
They stopped outside the bathroom, and John raised an eyebrow.
They quickly discovered that Sherlock was just as adept at picking locks with this left hand as his right.
Moving about with a mad genius attached to your wrist was not a particularly pleasant experience, especially given Sherlock's tendency towards sharp and abrupt hand movements. John, trying desperately not to think about how damning it would look if someone were to find them, finally grabbed Sherlock's hand in his before his wrist broke.
"Excellent!" Sherlock cried, examining their clasped hands like they were a previously undiscovered type of cigarette ash. "It takes the pressure off of our wrists and allows me to control your movements better."
John, who was still standing on top of the kitchen table, having grabbed Sherlock's hand mid-climb, frowned.
"Why are you controlling my movements? Maybe its for me to control you," he replied.
"I am the consulting detective, of course I'm the one in control. You are the blogger who can't even remember the simplest parts of our code," Sherlock said.
"I'm learning! I remember some of them-" John started, heatedly.
"-'Vatican Cameo'," Sherlock cut in. John blinked. Sherlock smiled evilly and dropped to the ground, pulling John off the table. He landed heavily on top of Sherlock, who was not a very comfortable cushion.
"I thought I should take a more hands on approach to your learning. I guarantee you'll remember 'Vactican Cameo' in the future," Sherlock said, a smug grin in place.
John pushed himself up on his forearms to glare properly at Sherlock, ignoring their hands, which were still clasped together near Sherlock's head.
"I didn't suggest we do this for you to humiliate me-"
"Oh, its nothing of the sort, I-"
"Oh dear!" Mrs. Hudson exclaimed, standing in the doorway of the kitchen. "I'm sorry, boys, I didn't know you were busy, I'll just let myself out." She winked at them before turning around.
John groaned and flopped back on top of Sherlock, burying his face in Sherlock's shoulder.
"I think we've practiced being handcuffed together enough now. If it, God forbid, happens, we just need to remember to coordinate and take it from there."
John rolled off of Sherlock, and they stared at one another a beat before laughing. John tugged on the chain between them gently.
"Come on, you mad wanker, pick the locks on these again. It's my turn to set you on fire."