Morse
A/N: Credit goes to Tumblr again. This time to whomever made up the head cannon about Sherlock needing an outlet to say he loves john and tapping it in Morse code. Then the follow up of john getting fed up with it and tapping "I love you too, you stupid git" back at him. It was cute so I wanted to expand it. I planned to upload it on the 29th for their anniversary but oh well, life happened.
"∙∙ ∙-∙∙ - ∙∙∙- ∙" = I LOVE YOU in Morse code.
"∙∙ ∙-∙∙ - ∙∙∙- ∙ - - - -∙- - ∙∙- -∙ ∙∙ -"= I LOVE YOU TOO YOU GIT in Morse code
Sherlock
After much deliberation, research, and attempts at acceptance Sherlock Holmes discovers he is, in fact, capable of love. Not only that but he is currently suffering from this defect thanks to none other than John Hamish Watson. His "Not Gay" flat mate. It is for that reason that Sherlock says nothing about this discovery; he keeps it stored in a trunk of the Mind Palace's attic.
If only the thought would stay there… It's nearly impossible to keep it locked up. For example Sherlock now notices how much he notices John. He can't seem to pin down when he's begun to pay so much attention to John's jumpers, John's expressions, John's everything. Its stranger still to find a part of him is constantly thinking about John. Upon closer inspection the John folder in the Mind Palace's library had morphed to its own room full of packed novels of information.
The affliction only worsened from here. Sherlock finds himself staring more and talking to john even when he is nowhere inside their flat. Another discovery: Sherlock felt John's absence and worried about the man while he was gone. He also finds himself becoming much more jealous of any women John decided to go on dates with. Originally he'd thought it jealousy of wanting his friend's attention but now a dark monster had hold of Sherlock's heart. It enjoys rearing its ugly head at any interaction between john and another interested party.
This "Love" disease was starting it become physically painful. It only seemed to keep building up in attempt to burst him at the seams. That or at least shatter every bone in his body. An outlet was needed before it kills him, he decides while watching a sleepy john make tea. As a test Sherlock taps out: ∙∙ ∙-∙∙ - ∙∙∙- ∙
John pauses a millisecond but otherwise continues as normal. "Wondering what the rhythm is." all stays as normal. Sherlock from this point on taps this same thing every chance he gets. John seems to either ignore it or not notice at all. The detective is thankful. He values John too much to scare him away with this. The Morse is a double win really: He can express his damned emotions and keep John happily unawares.
John
The first time John hears the tapping he almost discounts it as background noise. The inner soldier of course was looking for a pattern; force of habit more than anything. When it comes together as "I love you" he knows it's just him being silly. Sherlock wouldn't be doing that intentionally. It was probably an absent rhythm. So John ignores it and finishes his tea up. Besides, he's too tired to analyze anything anyway.
The funny thing is, though, that it kept happening and at the most random times. It could be any time of day anywhere and on literally every surface available, Sherlock was tapping out that same rhythm constantly. On the mantle looking at evidence when John brings him tea. On his knee while he watches John typing. On Lestrade's door. On the back of his phone. Going up the stairs. Cab windows, lab counters, his chin, John's chair, and even John's arm a few times.
Over a month John puzzles about this new quirk of Sherlock's. If he'd been composing John would connect it there but no dice. And the cases have been small with no connections to each other so it can't be that. It was too deliberate to be absent minded taps. Well as Sherlock himself had said "take away the impossible and whatever remains, however improbable, must be true," Sherlock really was writing "I love you" and it doesn't take a genius to figure out who that message was meant for.
Now that opened a totally new can of worms. It's not like Sherlock had ever expressed sentiment for a human before. Did he mean it platonically like brothers? Or was it romantic? Would he set aside The Work for a relationship? How did he feel about this himself? Most importantly did Sherlock know he knew Morse code?
Time to stop beating around the bush. John knew from the cabbie on that he cared about Sherlock. He'd given up plenty of girls for him, had started dating girls who reminded him of Sherlock. He adores all the quirks and craziness of the man. Even if it was maddening sometimes. It was most assuredly love and the object of his desire was driving him up a wall with his incessant tap tap tapping on the counters right now.
John turns around from cooking with an exasperated sigh. Quickly and with quite an attitude he taps out his reply. "∙∙ ∙-∙∙ - ∙∙∙- ∙ - - - -∙- - ∙∙- -∙ ∙∙ -"Sherlock's entire lanky form whips around with mouth agape; just staring.