What The Hell Are You Doing?

A/N: For the waiting. To tide us all over until the monstrous-project-I-have-been-working-on-since-October is completed and posted… My thanks to KoraM852 for the phone-beta!

Disclaimer: All the things belonging to other authors, writers, creators, and…people who own stuff. I claim nothing… but theory…

"What the hell are you doing?"

Sherlock wiped the glass in a single motion, powder spraying the floor.

John stood aghast in the doorway, one arm up across the paneled wood. He stared between Sherlock and the square of glass on the coffee table, so often covered by the debris of their daily lives...

"What was that?"

Sherlock saw the wheels turning in John's head, the doubt and disbelief. He had seen all of that flicker through his eyes on their first day together. The day that John had learned, rather by accident-what with the impromptu drug raid Lestrade had set up in the flat, that Sherlock was...not unfamiliar...with choice varieties of substance use.

"No. No. This is not what you're thinking."

"Sherlock, so help me... I'm trying not to jump to conclusions here... But if you say this is for an experiment…"

He slumped against the door, no longer able to look at his flat mate.

"Mrs Hudson called me, you know. She was worried about you. Said you were too quiet today: no explosions, no potential clients running out in tears, no violin...and, Mycroft hadn't been by to check in... She thought I should come home. So, here I am."

John pushed off from the door.

"This has got to stop."

"John. I was not snorting cocaine. The powder is not drugs."

"Then tell me why you tried to hide it. Why brush it off the table? You've never cared for housework, so don't you dare claim you were dusting."

"I will never lie to you. I don't tell you everything, I know. But I will not lie. I was not dusting. Neither was I doing drugs."

"Then what?"

"It was an experiment. This powder—"

He waved at the particles layering the floor.

"-is Iocane, finely processed. Historically, it was used to treat mental illness...anxiety, depression...ulcers... It's more apt to use as a slow-working poison, in certain dosages. I've been working at building a resistance to it."

"Why on earth would you do that? Do you think some one is going to poison you?"

"We can't be too careful."

"We?"

"Yes."

"We."

"That is what I said, John."

John sighed, his hand moving up to scrape at his brow.

"Have you been slowly poisoning me, then? Lacing my food, my drink...Sherlock have you been putting that in my tea?"

Sherlock didn't speak. His brow lifted, his mouth turned down slightly.

"Jesus, Sherlock."

"Have you felt any ill effects?"

"Are you that much of an idiot?"

Sherlock gaped.

"I am not an idiot."

"You are though, a genius idiot."

John moved into the room, sitting down on the couch. He leaned down to brush a finger through the dust. He lifted it to his nose, carefully drawing in a breath. Odorless. He tapped his tongue against his fingertip, rolling the grit around in his mouth for a moment. Tasteless. He spat out the residue in a wayward dish towel he pulled from the arm of the couch. Likely, it had been off-handedly used to carry some hot dish...

He looked back to the detective. Sherlock was watching him. No doubt cataloging and analyzing his tests and reactions.

"Where did you get this sample, anyway?"

"Hmm? Oh, Lestrade's latest case. The victim worked at a university lab. No identifiable cause of death. I propose the victim died of acute Iocane poisoning. Virtually undetectable, as it metabolizes so rapidly. He would have had to consume a great quantity in a rather short period to be killed by it, without showing signs."

"Signs."

"Yes. Long term exposure can be evidenced by loss of hair, jaundice of the skin and eyes…"

"Can you hear yourself? Are we going to loose our hair and die from this…resistance-building?"

"Of course not. I've kept the doses small. No lasting effects."

"No lasting effects? Any non-lasting effects?"

"...Any changes in mood or behavior? Sexual appetite or stamina?"

"I think you'd know... Well, about the mood or behavior bit... Not the... Never mind."

"What if I did? You haven't had a girlfriend in a while, John. How are you feeling? Any changes in libido?"

"I am not discussing this with you."

"It's important, John. It could be a sign that I've made a drastic error in calculation."

"It's fine."

"No. It's not."

Sherlock leaned in, his hands fluttering over the doctor. Fingers pressed to his major pulse-points...carotid, brachial, lymphatic... He pulled back his eyelids, peering closely. He pulled up John's shirt-back and pressed his face against his ribs, ear just below the shoulder blade. He tapped his fingertips to John's ribs, listening to the echo reverberating through his torso.

"Sherlock, stop it."

Sherlock hummed curiously.

"Speak again."

John sighed.

He chuckled once.

John felt a lance of heat shoot through his chest. He asked, cautiously.

"What?"

"It sounds funny...feels funny."

Sherlock sat up, rubbing his cheek. He looked at John, catching the dark look he cast at him.

"John... Why don't you have a girlfriend?"

"The last one brought it to my attention that... Well, my interests are rather otherwise engaged."

"Is that so?"

Sherlock sat still, his eyes holding John's.

They sat unmoving. John's clothes lay gathered oddly. They bunched at his neck and upper arms, in mild disarray from Sherlock's investigation of his health and well-being, Sherlock's hair having gone wild on one side.

Taking rare, independent, impulsive action, John moved his hand up into those curls, ruffling the flat side of Sherlock's hair. He traced his finger around Sherlock's ear, touching at the soft inner ridge. He leaned in slowly, brushing his lips to the other's.

"There's nothing the matter with my libido."

A/N: INCONCEIVABLE!