AN: Hello everybody, thank you for all the reviews and alerts and things. Sorry it took me a little while to post this chapter, I had to rework the beginning a bit. I hope you all enjoy it and please review and tell me what you think. Thank you. :)

John was watching Sherlock mutter to himself in a way that he knew meant the detective was frustrated. The doctor shifted slightly on the uncomfortable metallic stool providing the only seating in the cold laboratory and sighed. It was near midnight, he was tired, and once again Sherlock had forgotten that the majority of humans required food at some point between midday and dusk.

"Agh!" Sherlock pushed the microscope away from him violently and began pacing feverishly. He paused, glared at the ceiling mournfully and began pacing again. John was simply too tired for this and made his way over to the microscope.

Navigating past Sherlock's still pacing body he rested slightly against the side of the bench, pulling the rejected microscope closer and peering down it, after adjusting its height of course.

"It's blood Sherlock. Just plain old human blood. What's the fuss about?" Sherlock turned to give John a look that told him he was clearly being stupid again.

"John! It's not what is there that is irritating me- it's what isn't there. Look!" And with the command he marched over to John, reaching around the doctor's shoulder to point at a half open forensics file, pressing himself almost completely against the other man's back, trying to look down the microscope again, over John.

John cleared his throat, shifting slightly at the new level of proximity but finding himself trapped by the table, sighed and simply reached for the file.

"Ah, I see." John tried to rub his eyes but found his movement impaired by the fact that Sherlock had resumed his examination of the blood sample, simply ignoring the fact that John was stood between him and the desk. John groaned to find himself imprisoned by two thin, strong arms, Sherlock's chin resting slightly on his head.

Too much. This was too much, he was tired and hungry and-

"Yes, this blood is the headless man's. Therefore you see my problem; both you and I concluded he was injected and that this was the most likely cause of death based on the evidence of what was left." John had almost forgotten he had spoken and was slightly startled at Sherlock's reply, disconcerted by the way he could not only hear the detective's voice, but feel it rumbling through his chest.

Sherlock stepped away from the slide, releasing John and frowned at the ceiling as if it were hiding answers from him. John shivered unconsciously at the lack of warmth he realised his tired body had begun to lean in to. He yawned.

"I don't know Sherlock, you're always the one that says –what is it? Once the impossible's eliminated-"

"Once you eliminate the impossible whatever remains no matter how improbable must be the truth- of course! John you're a genius!" He seized the doctor's shoulders, grinning. John just blinked tiredly, accepting the compliment he had no idea how he had earned.

"We know that the victim was killed by a lethal injection, but we also know there is no trace of such a thing in his blood. Ah –clever!"

"Clever?"

"Air John, air!" Sherlock seemed almost ecstatic. "Just a tiny bubble of air pushed from the syringe into the blood stream. As soon as it got to his heart," he unclasped his hands abruptly, "his heart would stop, and the cause would be almost undetectable." He tailed off in a whisper, his hand placed over John's heart, envisioning the dead man and portraying a look of wonderment.

John however, was not overjoyed to be being compared to a corpse.

"Well, congratulations. Deduction made, point to the genius –please Sherlock, can we go home now?"

Sherlock glanced up and seemed to finally take in his flatmate's state of exhaustion. His forehead puckered slightly into an almost imperceptible frown. He reached around John, pulled a phone out of his friend's back pocket, sent a quick text message, and then nodded.

"Yes, it appears if I keep you awake much longer you may collapse." He reached around to slide the phone back into the doctor's pocket. "Come on, it shouldn't be hard to find a taxi."

It was the afternoon after Sherlock's ecstatic discovery and John was in the kitchen trying to open a tin of beans with a tin opener that was jarring suspiciously.

"Sherlock, have you been using the kitchen utensils for your experiments again?" He clenched his teeth in a forcedly calm manner as the blade slipped, making a jagged cut into the side of the tin for the third time.

"If it's that thing with the white handles I may have used the circular blade last Tuesday to aid a dissection but I assure you I reassembled it afterwards." John dropped the tin and opener as if he'd been burned.

"You used it in a dissection –Shelock! This is stuff we use for food, cooking, stuff that shouldn't be combined with dissection-not that you'd know anything about it of course with your aversion to all things human." He spoke harshly through clenched teeth. After returning to the flat in the early hours of the morning, Sherlock had decided he needed to think and the persistent plucking of violin strings had prevented John from sleeping till almost dawn.

Needless to say he wasn't in the best of moods.

Sherlock looked at John from where he was sat at the table examining crime scene photographs. His face was unreadable, but his eyes seemed maybe just a little bit... hurt. John rubbed his hand across his face, turning back to pick up the fallen tin but dropped it again suddenly.

"Ouch!" He clutched his hand tightly. One of the jagged cuts in the body of the tin had caught him as he picked it up and gouged out and impressive amount of skin at the base of his thumb. John quickly examined it, concluding that it wasn't deep enough for stitches, whilst hissing slightly at the pain. He was about to move over to the sink to clean it when Sherlock's hand gently lifted John's wounded one towards his face. John was rather startled by the movement and watched the detective's critical gaze quickly examine the cut before raising it to his mouth.

John froze.

Sherlock had calmly closed his mouth around the base joint of John's thumb and had begun sucking lightly, his tongue occasionally tracing the injury. His hand gripped John's firmly so he could not pull away. After a minute, he looked up.

"Sherlock, what the hell are you doing?" The question came out evenly but in a pitch a fraction higher that John's normal voice. Sherlock looked at him, quirking his eyebrow slightly.

"I'm cleaning your wound whilst administering a mild anaesthetic. Surely as a medical man you have read all about the healing and pain killing properties of saliva- therefore you will agree I am performing the action that makes most medical sense."

John felt the need to cover his face with his hands, his cheeks holding the faintest of disturbed blushes at the mention of saliva.

"We have a tap." John yelped slightly. But Sherlock merely sighed before bringing the wound back towards his mouth.

John really didn't know what to do with himself whilst Sherlock 'attended' to his hand. He felt awkward just standing there with part of his hand in his flatmate's mouth and the feel of Sherlock's lips against his skin were slightly disturbing. He noticed they were slightly chapped.

"There we go, seems to have stopped bleeding. How's the pain?" John merely stuttered in reply.

"F-fine. Yeah, fine." And with that Sherlock turned back towards his mess of papers on the table and seemed to give John no further thought. The doctor shook himself slightly, and then decided to go to the bathroom and find a plaster.

He re-entered the kitchen uncomfortably on edge. "We're out of milk again. I'll just pop to the shop." Sherlock gave no answer. "Right."

"Oh John, wait." John turned around quickly. Sherlock held a hand out. "Phone." John restrained from rolling his eyes as he handed his phone over to the detective. He needed some fresh air.

As he walked round the crowded supermarket John kept trying to imagine how a normal person would react to Sherlock's unique form of first aid. They'd probably find it creepy, he thought. But then most people didn't get that Sherlock had little regard for simple things such as personal space and appropriate social interaction. In fact most people thought Sherlock was a bit of psychopath. Which was foolish really, Sherlock just... he was able to appreciate the brilliance of an action whilst detached from its moral implications.

John sighed, picking up a carton of milk and heading towards the checkout, making sure to find one manned by a human. On the way past a small rack he paused, and, almost involuntarily, picked up a small pot of lip salve.

When he got back, Sherlock was lying despondently on the sofa, glaring at the ceiling. John waited for a minute.

"I'm back." Sherlock merely grumbled.

"Did Lestrade cut you out again?" Sherlock's only reply was to turn to face the back of the sofa. John took that for a yes. Lestrade had taken to banning Sherlock from accompanying him on routine interviews, apparently he scared the people too much with his startling lack of empathy.

John went over to the kitchen and put the milk away, ignoring the severed ear resting in the meat draw. He moved back to stand over Sherlock and held out the lip salve awkwardly.

Sherlock blinked.

"I... your lips are chapped." Sherlock frowned slightly at him but took the small pot. John scratched his head. "I wanted to apologise. For saying you weren't human, you are human you're just... Sherlock. Anyway, er, thanks, so, I'll go... yeah." He cleared his throat awkwardly. Sherlock stared at him, then nodded.

John dropped himself unceremoniously into the arm chair on the opposite side of the room, picking up the newspaper to hide behind. Maybe Sherlock's social ineptitude was rubbing off on him. He sighed and began reading the recent cricket scores.

One day he would teach Sherlock about personal space, one day –soon.