Every Tuesday without fail, John would go and do his laundry. He had found through trial and error that Tuesdays were when the launderette was least busy. Families and weekday workers did their washing on the weekend, and weekend revellers were in on Mondays, trying to get rid of the stains and remains of their partying. Tuesdays were calm in the launderette.

Every Tuesday morning, John set off with an Ikea bag full of the week’s dirty laundry, a supply of coins and a book, and would sit strangely comforted by the sounds of the machines and enjoying the chance to get immersed in a novel for a few hours without being interrupted by the demands of his irritating flatmate.

Being conscientious, he always checked the pockets of his trousers before putting them into the washing machine, even more so after the almost-disaster involving a pair of jeans, a paper napkin, and a small plastic zip-lock bag filled with some strange chemical that Sherlock had asked him to keep hold of at a crime scene.

Of course, Sherlock knew about this. He always seemed to know about John’s habits, regardless of whether he saw them or not. So Sherlock had developed a habit of his own. He would put small handwritten notes into the pockets of John’s trousers.

We’re out of milk. Can you pick some up on your way back? read the first one. John sighed when he read it, folded it up into his wallet, and got the milk.

Don’t worry about the stain in the bathtub, was the second note, it’s harmless. Of course, John worried, and made Sherlock clean it, though Sherlock protested that it was an experiment.

Mycroft has another case. I told him to go away. He might call you. John appreciated the warning, because of course Mycroft called. As if John had any influence over whether Sherlock took a case or not.

Every Tuesday without fail, there would be a note in John’s trouser pockets. Small things, mundane things, asking him to get something, telling him about experiments, calm little asides in the usually hectic and turbulent life in 221B. When he arrived at the launderette, John always checked his trouser pocket first to find the next message. Regardless of their content, the notes always made John smile, especially when they had a more chatty quality.

I dreamt of the Queen last night. She waved at me, and I waved back. What would Freud say? That note John kept in his wallet for a long time before putting it in the little box where he kept all the notes. Sherlock would scoff at the sentiment if he knew, unless of course he did know and ignored it.

Sound cannot travel through vacuum. Just one of the mistakes in the film. But watching it with you was not too bad. This was after John had watched Star Wars while Sherlock had apparently worked on his laptop.

I’m bored when you’re away. That was probably the shortest and most heart-warming note John had found in his pocket. Of course, Sherlock never voiced these thoughts aloud or spoke of the notes, but while he did the laundry that Tuesday, John found he couldn’t concentrate on his novel. He knew that he and Sherlock had grown ever closer over the months they had shared a flat and ran around London catching criminals. He was certain that they were friends. He would certainly call Sherlock Holmes his best friend, and if John entertained more romantic thoughts about his flatmate, well, these would stay quite firmly in John’s mind and in his bedroom.

Then came the Tuesday when there was no note in John’s trouser pocket. The weekend before, they had closed a case after a mad dash through Holland Park. In a last-ditch effort to evade them, the criminal had pushed John off the ornamental waterfall and into the koi pond of the Kyoto Garden. John had surfaced sputtering, bruised, bleeding from a cut to his forehead, and watched in a daze as Sherlock tackled the fugitive to the ground, knocking him unconscious with some force, then jumped down to where John was sitting and pulled him out of the water, questing fingers making sure that John was not seriously hurt. In his dazed state, it appeared to John that Sherlock was fussing over him, but surely, that could not be.

There was no note that Tuesday. John did his best to squash his disappointment. Sherlock must have gotten bored with this little game, and John couldn’t exactly demand that Sherlock leave him notes again.

But stranger was the Tuesday after that. There was a piece of paper in John’s trouser pocket, the same paper that Sherlock usually used when leaving John notes, but although it was carefully folded, it was empty. Thinking that perhaps Sherlock was using an invisible ink just to annoy him, John dredged up all his childhood memories of how to make invisible ink visible, but none of his efforts were successful. The paper was empty, as was the next one.

This was too strange for John, and when he came back with the Ikea bag of freshly-laundered clothes and saw Sherlock leaning intently over his microscope, he decided to mention it.

“Empty notes, Sherlock? What do you want me to deduce from them?”

Sherlock hummed, then said, “Deduce what you wish, John. Now go away and stop interrupting me.”

“Git”, John said, turned around and carried the Ikea back up to his room. He’d never speak of the notes again, but he couldn’t bring himself to throw the old ones away.

A week later, there was a note again. We’re out of milk. Can you pick some up on your way back? John was annoyed at first, until he remembered that it was the exact same note that Sherlock had first left in his laundry. “Sentimental bastard”, John chuckled to himself. “Sociopath my arse.”

There was another note though, tucked away in the breast pocket of one of his shirts. When he unfolded and read it, his knees went weak, and he had to sit down on one of the hard plastic chairs in the launderette, heart racing, trying to think. Swallowing hard, he nodded once to himself as he reached a decision. Then he was running back home, laundry forgotten, the note clutched in his fist, back to 221B, taking the stairs two at a time, opening the flat door to find Sherlock standing there, dressed immaculately in his suit, looking at John with apprehension.

John dropped the note to grab both lapels of Sherlock’s jacket, tugging down until their faces were on the same height. He leaned in and very softly, very carefully kissed Sherlock’s lips. Sherlock shuddered, and after a moment’s hesitation reached out and drew John into a hug that felt as if he never wanted to let go, and that was fine with John. He felt the same way.

It was the last note that Sherlock would hide in John’s laundry, but the most important one he’d ever written. It simply read, John, I love you.