Author's note: So this is based on a Fatlock Scenario I submitted to .com. However, then it wouldn't leave my brain alone so now I am turning it into a full fledged fic. Hope you enjoy! It turned out a tad plottier than I had intended. Kink galore in next chapter(s) I promise!

The morning light peeked in through the window, between the curtains which seemed to have been neglected last night. This allowed the sunlight to prod the eyelids of one John Watson who huffed in his sleep and blinked himself awake. He grumbled and rolled onto his side to face away from the unwelcomed call to wakefulness. He sleepily registered the form of his consulting detective turned mad flatmate, turned lover before closing his eyes again. What was odd was that Sherlock had taken the right side of the bed when he always made such a fuss about wanting the left. Well, maybe they had both been rather tired last night. John frowned. He actually couldn't remember going to bed last night at all. He hadn't even been drinking. John felt something tickling his forehead annoyingly and reached a hand up to brush it away. Maybe a spider or s-

No. God his hair really was getting long... but it didn't curl like that. And his hand felt entirely too big to be his own. John opened his eyes and gave a small start of surprise and a well chosen swear as he took in the limb before him. It wasn't unfamiliar. Just utterly alien in it's current location before his eyes, long and pale with slim violinist's fingers. John's eyes trailed down to where it connected to a slim boney wrist and forearm that definitely did not belong to him.

"Sherlock?" asked John and his voice reverberated in his chest in a way it definitely wasn't supposed to.

The form next to him grunted and rolled over and John let out his second well chosen expletive of the morning, followed by his third, fourth and fifth in quick succession. Because it wasn't Sherlock laying next to him. It was John, himself.

John took in his own face with some sort of quasi fascination. It was like a three dimensional mirror or some odd way of seeing himself on tape. Still, that couldn't be him. He was him and whoever that was was definitely not him.

Actual John felt his heart begin to pound. Was this some sort of trick by Moriarty? Another of his games? At any rate. That wasn't Sherlock lying at his side. John pounced, and pinned the stranger who looked like him to the mattress by the throat. His limbs still felt abnormally long and slighter than what he knew his own felt like, but they were wiry and strong. The man who looked like him gave an indignant yelp and struggled for a moment before staring wide-eyed up at his face, blue eyes flicking around every feature with surprising speed.

"All right," growled John, and it definitely was a growl, deep and resonant in his own head, "Look I don't know who the hell you are, or why you look like me, but where's Sherlock?"

Not-John raised a shaking hand to the one John had around his throat, then snarled in John's own voice, "You're strangling him. But the better question I think is who the hell are you? Some genetic experiment? A clone or just a very convincing doppelganger?"

John blinked. It was odd hearing that rapid fire speech come from his own lips, see his own eyes dance the way Sherlock's did when he was taking every particle of something in.

"No..." said Not-John after a while, looking up at John, narrowing his eyes, "John Watson, I presume? We seem to have woken on the wrong side of the bed."

John watched his own mouth try to quirk into the half smirk that always appeared on Sherlock's lips when he was being clever.

"Yeah," said John, loosening his grip on his look-alike's throat and lifting his hands to look at them, "Hang on, so if you're in my body, then-"

"Yes, yes, you're in mine," said Sherlock, rolling his eyes, "Do keep up."

"But- How? Sherlock, how in the hell did-"

"African dream root, or Silene undulata if you prefer," said Sherlock, wriggling John's body up against the pillows and steepling his fingers beneath his chin, "I was conducting an experiment with it. You were a participant, I hope you don't mind, I needed more data."

"Sherlock, did you fucking drug me? Again?" snapped John.

Sherlock's, or well John's, eyes flicked back to him. "Yes. Really you should be more particular with your tea. I suppose this is a good time to check if your palate really is completely shot or it's just your average- er. Sorry," said Sherlock, and thanks to John's face he actually looked it for once. He paused then added, "I should have asked you. That was... that was a bit not good, wasn't it?"

John huffed a sigh and it sounded more exasperated when coming from Sherlock's lungs. "Yeah. You kinda should have," he said, dully, looking down at his mad scientist of a boyfriend. Luckily his curiosity was getting the better of his anger for once.

"So, er, what does that African dream root actually do?" he asked.

"It's a plant that has a rather interesting psychoactive element in it that hasn't been identified by modern science yet," explained Sherlock, the details rattling off John's tongue with all the confidence they normally did. God, his own voice really sounded like a posh twat when he enunciated like that. "It has been used in African spiritual ceremonies for ages. Now as you know, I don't usually go in for that sort of thing, but the compound intrigued me. It is said that it allows the consumer to dreamwalk when sleeping and manipulate another person's dreams. Out of curiosity. Did you have any... er, dreams an interesting nature?"

John felt Sherlock's cheeks rush with heat as he remembered. "Er, yeah. They were. They were really quite... good," he said. He was pretty sure at one point there had been two Sherlock's being rather imaginative.

Sherlock chuckled, John's laugh coming out instead. "Well, glad to see that was a success at least. I had been worried. You are supposed to take it on an empty stomach and I didn't manage to get yours to you until after you'd had dinner," he said, "My guess is that we both wound up dream walking and walked into the wrong head once we settled in for the night."

"Ah, I see," said John. Though he really didn't. Sherlock suddenly clapped his hands together and leaped out of bed.

"All we need to then is to induce the dream state again and get back to the proper bodies," he said excitedly, rushing over to his wardrobe to pull out his usual suit and trying to dress John's body in it.

"Er, Sherlock," said John pointedly, nodding to his own instead and grinning.

"Oh, yes right." John watched himself give up on the too long and too snug clothing and go burrowing through his jumpers instead.

"Oi! I just folded those!"

"No time, John. I'll get this mess sorted again. I need to meet up with my contact before she leaves town again or we'll be stuck like this for God knows how long," replied Sherlock, straightening and checking himself in the mirror. John watched a frown furrow his brows when he wasn't tall enough to see all of himself and he chuckled.

"Glad you're enjoying yourself," said Sherlock flatly, swinging around in response to John's laugh. John wrinkled his nose up at him and pulled a face. The detective in the doctor rolled his eyes and huffed, "Kindly stop doing that to my face, it's unbecoming. I'll be back in a few hours. Bye." With a kiss, he was gone, dashing down the stairs.

John sighed and decided he may as well get out of bed too. He undressed and redressed in Sherlock's clothing. God, how was that man even comfortable in these tight shirts all day? He ran a hand down the pale slim stomach and over the hipbones that were protruding beneath that. "Don't you ever eat?" wondered John aloud. The stomach beneath his hand surprised him with a growl. He couldn't help but feel a small rush of triumph. "Hah! You do get hungry, you prat," murmured to himself. Well, best to take care of this body while he was in it.

John wandered to the kitchen, walking a bit slowly since he felt like he was on stilts. He made tea and popped some bread in the toaster. Then decided he could do with some eggs and sausage as well. The smell of food was just making him hungrier. He wondered when the last time this body had had a proper meal. Well, at least Friday night when John had shoved a bowl of pasta at him.

Breakfast made, John settled down to eat. Sherlock's stomach seemed to gurgle in thanks as it filled with nutrients. John gave it a pat.

He was just finishing the last of the daily paper when he heard the door open and slam below, then feet on the stairs.

"John?," huffed Sherlock, pulling a scarf from John's neck as he rushed into the kitchen, "I managed to meet her, I got the last of the- what in God's name are you doing?" He stared at the nearly cleared plate and utensils sitting in front of Sherlock's body as if he had never seen breakfast before.

John raised one of Sherlock's eyebrows and replied,"You tell me. You're supposed to be the detective."

Sherlock narrowed John's eyes and glowered at him. "I'll ask you to look after my transport properly while you're in the thing. It doesn't require the level of fuel you flood your system with."

"Oi," said John, looking up indignantly.

But Sherlock was still on a tirade and bulldozed over him. "Even now, this body is so dismally sluggish. Slow. Soft! No wonder-"

"Sherlock. Shut it." warned John.

Sherlock did. He blinked down at his own eyes that burned at him. An almost apologetic look flicked in his eyes.

"I- I didn't mean. I actually," he began, looking apologetic. He shook his head and thenwas off again, dropping a paper bag on the counter and beginning to jabber away about the dosage and just replicating their same routine from the night before. His eyes flicked over and John crunched Sherlock's teeth through another bite of toast.

Sherlock used John's throat to swallow and then drew his notebook over to review the proper dosages they would need tonight. A pale long-fingered hand pushed a plate of toast towards him. Sherlock reached out and cautiously took a slice to munch on. Well, John's transport would need it. It wasn't used to working on little more than caffeine like Sherlock's was. John's palate seemed perfectly fine, it lit up in response to a good marmalade. It was different being John Watson, mused Sherlock. Warmer. The small belly brushing against his clothes didn't feel bad. Not at all actually.

Sherlock shook John's head and went back to his calculations. Everything would be back to normal tomorrow.