Author's note: Please bear in mind that this was written before the broadcast of His Last Vow. So should the last episode change anything (as it undoubtedly would), do note that this was written with the mindset that lacks any insight to that last episode.
The sun was beating through the windowpanes of 221b Baker Street into their- no, his living-room, when John Watson's head snapped to the direction of his voice.
After exchanging a few more sentences that, as anybody would have guessed, did not do the least to facilitate their communication, John rolled his eyes from his seat in the old-fangled red-and-green armchair that used to reek of black coffee but didn't anymore after Sherlock's return, and shifted so that he was sitting faced the detective.
"Let me get this straight," John gestured with a hand-motion that looked like he was doing a single vertical handshake with the air in front of his ear, disbelief in his eyes clear as a new cover-slip, "You are offering to teach me how to dance?"
"You heard me the first time round John," Sherlock frowned. "The fact that you elected to repeat the question only left me to conclude that you were unsure whether or not to accept the offer. I am inclined to believe that my question was sufficiently straightforward, hence it brought me to a second question: what was it that made you sceptical? I suspect that-"
"Stop," John raised a hand to put an end to his ramble, the little man sighed and rubbed the back of his neck. After a swift glance at the doctor, Sherlock quickly filed the information away into his 'Work' storage. Doesn't like the serviettes that Mary picked. Why? They're peppered with clear, glossy little bikes. John developed a distaste for bikes after 'the incident'. Wanted plain serviettes with matching coloured swan or the Sydney Opera House matte-pattern in a corner. Well, that's out of the picture now, the bike ones are bought. Rectify situation: Youtube. Fold. Serviettes. Sydney Opera House/Swan. Or both, both is good. Tuck bikes into folds.
"Yes, I do know how to dance," he replied, deducing-no, knowing that John had asked the question.
Glancing up to meet John's eyes, he quickly added, "Not hip-hop."
John gave a small laugh that sounded a bit like bells. Dreadful church bells. Ring-a-ding-a-ding. Oh the big day... The big, awful day.
"So, what do you say?" He prompted, swishing the violin bow at his partner-in-crime-solving, "Are you going to let me teach you?"
"Are you sure?"
"John, something in your tone tells me you are doubting my sanity more than my ability to dance. If it would make things easier for both of us, I will ensure you that I am no more sane now than I was when that cab driver drugged me. So," he pressed, ignoring John's slow shaking of his head and a quiet mumble of 'an absolutely charming reminder, I killed a man that night.', and continued, "Are we dancing?"
Still staring distrustingly at Sherlock, John opened his mouth as if to say something, then closed it. He opened his mouth again - and then closed it again, but the moment when Sherlock's patience and - good manners - were just about running out, John raised both hands in defeat.
"Alright, alright! Since you came way out of your comfort zone with this offer, it's only fair if I contribute equally on my part. What dance are we doing?"
Sherlock set his violin bow down with one last flourishing whip, then hopped to his feet and strode over to the radio.
"The Waltz," he said, expression unchanging, "You and Mary will be waltzing at your wedding recession."
"-Reception," John corrected, "And what made you believe you are certified to preside over the progression of our wedding night, if I may ask?"
"I'm your best man, and recession or reception makes no difference. Both witness economic decline at varying degrees and different stages."
"That's not what best men do, Sherlock," John shook his head, but decided to let the matter about the Waltz drop. The army doctor got up to join his detective by the radio that was already emitting soft, silvery notes into the flat.
"Now what?" John asked, crossing his arms behind his back and rocking slightly on the balls of his feet, "Are you teaching me, or are you dancing with me?"
"...Shshh..."
Sherlock a raised his finger to his lips to gently hushed him, and spoke softly.
"Listen to the music, John. Close your eyes..."
Dancing... the only time when he let all his mental exercises hang.
"Close my-... Sherlock, what?"
"I'm teaching you how to move in time with the music, John," he snapped - God! Why couldn't this man just do as he's been told? - but then added a little more gently, "Now, just close your eyes, and follow my lead."
He placed his hands on John's upper arms, indicating that the other man should do the same. John did so a little awkwardly, and with a nod, let his eyes fall shut.
"Now," Sherlock continued, speaking softly over the music playing in the background, "I will be moving in time with the slow beats, so when I step forward, you step back."
"How am I suppose to know you're stepping forward? I can't see a damn thing!"
"In ballroom," he explained patiently, "The leader leads with their body, so whichever direction I want you to go, you'll feel the lead."
The frown lines on John's face told him that none of what he just said had made any sense whatsoever, but if he had questions, the smaller man obviously thought it better than to ask.
"One... Two, three," Sherlock began, pressing forward, forcing John to step back, "One... Two, three," angling to the side slightly so they didn't run into the cabinet, "One... Two, three-"
They went round the lamp. John tripped on the edge of the carpet but kept his eyes shut tightly, trusting Sherlock to not let them crash.
"... And One... Two, three- bend your knees a little more, John. That's it. Never lock your knees in the Waltz, keep them flexible. One... Two, three"
As they danced, the lines between John's brows gradually lessened and the thin line that was his lips pressing together relaxed. To the detective's satisfaction, John began to move more fluidly, learning to take directions from him.
"...Will any of this ever come into use?" the army doctor mused as he stepped unseeingly around a sofa. The bullet-punctured yellow face on the wall smiled down at them, "I'll be leading Mary, aren't I?"
"You'll learn," Sherlock replied shortly, and continued to lead John along the mantelpiece as the first song faded out. Then, suddenly, Leann Rime's voice was slurring out of the speakers.
So many nights...
I sit by my window-
"One... Two, three," Sherlock counted a little louder, not liking what he was hearing, but not wishing to stop either now that John was getting a hang of the movements.
Alone in the dark... But now
You've come along-
-And you, light up my life...
"Chin up, John."
You give me hope,
"Straighten your back."
"Give me a break here, Sherlock!"
...To carry on.
You light up my days...
And fill my nights, with songs-
Sherlock drew to a halt in front of the radio and slammed his hand down to put an end to the blasted song. John opened his eyes, confused, and Sherlock gave him a strained smile.
"Well done, that was very good. Well- when I say that I mean you still need to work on your rises and falls, but we'll continue tomorrow."
"Tomorrow?" John still looked confused, little beads of sweat clinging to the roots of his hair from the exertion - yes, most people fail to recognise that ballroom is a bloody workout - "Why not now? I was only thinking this might actually be fun."
"Because a cab had just driven off, suggesting Mary will be knocking on the front door right about-"
Knock, knock, knock!
"-now. Best Sunday dress, the one pair of stilettos she owns, J'adore perfume, an old Chanel purse - worn at the rim but very well treasured, given to her by a..." Sherlock's eyes narrowed. An ex-boyfriend who was still pining after her all these years. Either David or Tom...Oh? David it is. Tom's resorted to drinking. Time to play the high-functioning sociopath card again...
"...-An old acquaintance. Clearly she wants to go somewhere special. Quite likely it's the Ladurée at Harrods, considering the time. Now go get changed."
"J'adore?! How did you-"
"She uses only one perfume, John, you are bound to already know that. She either wears it or she doesn't. Judging from how she's dressed today, anybody could guess-"
"How the bloody hell did you know what she was wearing?" John's face was a mixture of annoyance and fascination, "You were dancing with me."
"I saw her from outside the window, John. Did it not cross your mind that I could not have possibly lead the dance with my eyes closed without crashing us both-
"I don't know, you're bloody Sherlock Holmes," his friend laughed as he gathered his jumper up from his armchair, looking more relaxed after having danced, "You might just have the contours of this room memorized."
Sherlock gave him a tight smile as he dug his hands into his trousers pocket, standing rooted to the spot.
"Yes, I might..."
The door shut behind him, and John's footsteps on the stairs faded into the distance.
Sherlock took a deep breath, and turned around, bending down to pick up the music sheets that the wind had swept to the floor.
As he scanned his eyes around the living-room painted with memory of the past four years, suddenly, the cramped little flat in the middle of London just looked a lot... bigger.
...Emptier.
The sun was setting outside his windows, leaving only a ray of orange light filtering in to sweep the room in with its bitter glow.
A cold breeze flushed in.
...and Sherlock shivered.