*Note: Everything is sort of pretty much the same except everything gets way naughtier after TGG. Includes eventual dark!john and lots and lots of dirty things. Enjoy.
The Law of Parsimony states that the simplest explanation is usually the correct one.
But there's nothing simple about Sherlock Holmes.
Turns out, there's nothing simple about John Watson either.
When John first sets eyes on Sherlock Holmes, he has no idea what he's in for. The instant he meets the strange man's eyes, he forgets all about his pain and Afghanistan and focuses solely on him. John's never been so engrossed in anyone before and he knows he'll fall in love like that again.
When Sherlock first sets eyes on John, he He forgets about the screaming needle marks on his arms the instant John smiles at him.
And soon they're off solving cases together like they're old friends.
John breaks all the rules. He is the exception, the loophole, the anomaly, the irregularity, the deviation. John throws a Molotov cocktail at Sherlock's cold, calculated, wall of logic and Sherlock worships him for it.
Sherlock decides to test him. He acts ruder than usual on purpose, and he invades John's personal space, and he brings up all the deep, dark history from John's past that he had so neatly locked away.
And John doesn't leave. (Correction: He can't leave. The magnetic pull of Sherlock is too strong, and John feels like a fly caught in a web, or a planet orbiting a sun.)
They go to the restaurant and John casually tosses out the neon sign that screams "NOT GAY". Sherlock's smile fall and he casually reminds himself why he doesn't fall in love.
And then John kills someone for Sherlock.
A sickening knot begins to twist in Sherlock's stomach as he realizes he's falling in love again, and there's nothing he can do to stop it. (He's not the spider weaving the web; he's the fly caught in it.)
Later (after the case is solved and they return to Baker Street, full of Chinese food), Sherlock goes into his room and silently examines his last needle full of cocaine.
He almost picks it up. Almost. But then he realizes he's got a new drug of choice: John Watson.
And wow, is he addicted.
Sherlock rarely eats, but when he does, John Watson is always sitting in the front row, watching his glorious, cupid bow lips move and imagining all the other things his tongue could be doing at that moment.
Oral fixation, he believes it's called (if he remembers high school psychology correctly). But that's wrong, because it's not a fixation. It's a fascination.
In reality, all of Sherlock is fascinating. But some parts (certain sensitive parts), are much more enamoring than others.
John can't help but watch the buttons on Sherlock's shirt, because they always look like they're about to pop off. John wonders how he can move with such grace in those impossibly tight clothes. (He almost wonders how Sherlock would move without all those tight clothes on...)
Once, after a long and particularly grueling case, Sherlock looks a little ill, and so John - being a good doctor - decides to take his friend's pulse.
"129!" John screams as Sherlock yanks his wrist away from John's grip. "One-hundred-and-twenty-bloody-nine!"
"You probably miscounted," Sherlock mumbles, as he turns to look somewhere, anywhere, but not at John.
John is almost lost for words. Almost. "Why's your pulse so high?"
Sherlock mumbles something incoherent and John is forced to come to a dangerous conclusion.
John grabs Sherlock's scarf before he has the chance to run away and stares right into the detective's eyes.
Pupils dilated, breathing erratic, elevated heart beat, skin flushed.
John comes to a conclusion. Unfortunately, it's entirely the wrong one.
"Drugs?" John asks, ready to call Lestrade or Mycroft or whoever the hell he's supposed to call in a situation like this one.
"In a sense, yes." Sherlock turns and stalks back towards his room. He locks the door behind him as John stands shocked in the hall.
John sits outside his room all night, just in case. All he hears is the the quiet melody of violin playing an unknown piece of music.
(The piece is called 'John'.)
The first touch is accidental.
It's been a long case, and as they climb victoriously into the back of a cab, Sherlock's hand accidentally brushes against John's.
Sherlock is overwhelmed. His senses teem with electric perceptions. (softsmoothwarmcomforthappylovesweetnicepleasant.)
(Sherlock blames the whole thing on sleep deprivation. John doesn't even notice.)
From them on, touch becomes a casual thing with them. John will occasionally pat Sherlock on the back, and he doesn't think anything of it. Sherlock - on the other hand - craves those little moments of intimacy. His mind buckles and reels at the idea of John touching him.
John doesn't notice when Sherlock starts standing closer to him than usual. Sherlock even starts doing little things for him, like opening doors, and paying the bills, and - even once - disastrously attempting to make tea.
They hug once. Sherlock's mind explodes and he stands, frozen, unable to do anything except replay the glorious embrace over and over again in his mind.
Sherlock is married to his work, but he's considering an affair (or perhaps even a divorce).