I neither own nor profit from any of these characters; they are the property of Sir Arthur Conan Doyle, Steven Moffat, Mark Gatiss and the BBC.

If you see something that you think ought to be changed or improved, please feel free to let me know, if you'd like. Constructive criticism is always welcome. (In this case, especially, as I know humour is not my strong suit, so please let me know how I might be able to improve!)

Written for a prompt from Feej – you can find Feej's great take on the bow tie at /s/6955990/4/.

Lestrade sighed, ran a hand through his hair, then remembered he had just combed it and withdrew, half a second too late.
"We're going to be late."
"We have forty-nine minutes."
"You've been in there for nearly an hour!"
Silence from the other side of the door. Lestrade shifted from one foot to the other, uncomfortable in his starched shirt and too-tight collar, his bow tie slipping askew each time he pressed his ear to the door to try to hear just what in God's name Sherlock was doing in there.
"Sherlock, I just want to wash up before we leave. Can't you do whatever it is you're doing somewhere else?"
"By my calculations, leaving isn't necessary for at least another twenty minutes."
"That's not an answer!"
Again, silence. Lestrade sighed and checked the invitation in his pocket again, just in case, by divine intervention, the time printed in the lower left corner had changed and they weren't going to be disastrously late if Sherlock didn't hurry up.
"Sherlock!"
"I am fully aware of your impatience, Lestrade, but attempting to hurry me by distracting me is contradictory at best."
In all fairness, the sigh that escaped him at that point through gritted teeth showed admirable restraint. Perhaps he needed a distraction.
Putting away the dishes in the drainer (not something he had ever planned to be doing in a tuxedo, but not even kitchen chores were normal with Sherlock around) kept him occupied for a few minutes, but no sooner were they all neatly stacked in cupboards and drawers than Lestrade was back at the door again, knocking impatiently. Still locked.
"Sherlock, what the bloody hell are you doing in there?"
Silence.
"I swear to God, I'm coming in there. And don't think I can't. You're not the only one who can pick a lock."
Silence, then a scuffling noise, and the door opened. Sherlock stood framed in the doorway, face scrubbed and hair as messy as ever. Lestrade took a moment to appreciate the way the tuxedo draped over his lean form, then asked, "What on God's green Earth kept you?"
Sherlock shifted uncomfortably, unwilling to meet his eyes. This could mean nothing good. Lestrade hadn't really been going to press for answers, but Sherlock's suspicious behaviour had changed his mind. "Well?"
"I… was merely attempting to prepare to the best of my abilities. You have made it quite clear that this event is important to you."
Sherlock might have been the world's best – well, only – consulting detective, but he was certainly not much of a liar. Still, they didn't have time for this.
"Hurry up and finish getting ready, then. You've already made us late."
"I…"
"What?"
"I… can't."
"Can't what? Why not? What have you been doing for the last hour?"
Sherlock scowled at him, then gestured dismissively to his collar, for all the world as though he couldn't possibly spare the time to explain himself.
Lestrade's eyes travelled to the crumpled strip of fabric around Sherlock's neck and rested there for a moment.

Then he collapsed in giggles, leaning against the wall opposite him for support as he gasped helplessly at Sherlock's predicament.

"You mean to say…" he wheezed, when he could finally speak again, "that you've… been in there for over an hour… because you couldn't tie your bow tie?"
Sherlock's glare was answer enough, and Lestrade succumbed to hilarity again.

"Why," he asked eventually, trying unsuccessfully to catch his breath, "didn't you just ask?"
Instead of a response, which he hadn't expected anyway, Sherlock glowered at him and said, "Are you going to help or not? I remind you that this is your event, not mine, and I am perfectly happy to stay at home and work on my skin decomposition experiments."
The thought of Sherlock's latest batch of experiments was enough to put a sober look on Lestrade's face, and he beckoned to the alleged genius across from him. "Come here."
Sherlock approached warily.
Lestrade caught hold of both ends of the tie, now quite the worse for wear, and deftly looped them around one another, pinching them into place and tucking the points of Sherlock's collar behind the neckband.
"There. All set now?"
If possible, Sherlock's glower had intensified. "How did you do that?"
"It's not difficult. You just loop the ends around – " and Lestrade loosened and re-tied his own bow tie, so that Sherlock could watch.
The detective narrowed his eyes. "I hardly see how that is a useful skill."
"Still haven't quite got it, then?" He was unable to keep the mirth from his voice, nor the spark of laughter from his eyes, as Sherlock's scowl confirmed his statement.
He shook his head. "We'd better leave. We're already abominably late. But tomorrow, Sherlock, you and I are going shopping."
"Shopping? Why? Surely we're not out of milk already."
"We're not," said Lestrade merrily. "But what we don't have is a clip-on bow tie."

He almost regretted saying it at the murderous look on Sherlock's face.

Almost.