The person who hypothesized that the passcode would spell out John's name had a good guess. Props on that one, pal. It wasn't a bad idea and if I didn't like this one so much, I would've used it.
Locks and Keys
John hadn't slept worse in his life.
Sherlock's phone sat on his bedside table, plugged in to a charger, its face glowing faintly with the time. John was staring at it, his hands tangled in the bedsheets near his pillow, wracking his brain for the passcode.
God, what is it? he wondered, getting more irritated. A rational part of his brain told him that it could just be a random combination— Yes, Sherlock would prefer that, it would make it harder to guess— and he knew Sherlock changed the code regularly. For the life of him, he couldn't figure it out—
…Wait.
Prompt was from Crimson Duchess, and it was: bed sheets