AN: WEEEE! This is my first Sherlock fanfic, (though there are DEFINITELY more to come in the future!) so please tell me how I did! I really enjoyed writing this and I hope you enjoy reading it! I was listening to some interviews with Martin Freeman (he's a funny dude, seriously) and I noticed just how much he swore! So I wondered if John Watson swore, with him being in the army and all. This is how my mind would play it all out :) ENJOY!

WARNING: Serious swearing, though letters are replaced with an asterix (*).

Foul Mouthed

"You know what John?"

"Mmm?" John said absentmindedly. He was busy typing up the last few paragraph of their previous case and he wanted to finish soon. 'Boring jealous lover' as Sherlock had put it. Still, John didn't know how he'd managed to figure out that it was a certain brand of nail polish that had poisoned the husband. The man knew too much about feminine products than was healthy.

John glanced up at Sherlock. He was sprawled out on the couch, the warm (and rare) sunlight basking the flat in an orange glow. Sherlock mumbled something in his deep baritone, but John missed it, his eyes riveted on the screen again. Crappy, daytime television was playing softly on the TV.

"Wait, what? I wasn't listening." John said, pausing his two fingered typing. Sherlock really did look like a lazy cat, he thought to himself.

"You know I hate repetition John" he admonished, stretching out "I said that you've had a rather negative effect on me that I've noticed recently."

"Oh?" John said amused. "And what's that? Not happy that I've managed to beat some manners into you? I think Mrs Hudson nearly had a fit when you invited her in for dinner the other night" he continued typing, smiling at the memory. Of course Mrs Hudson had ended up doing all the cooking herself. Sherlock chuckled and sat up.

"Actually think it's rather the opposite." John looked at Sherlock, genuinely intrigued. He had always been told that he was a good thing for his completely socially inept flatmate. If anything, Sherlock had had a bad effect on him. He was strangely immune to body parts and poisons in the flat now. Though he had put his foot down when Sherlock had tried to sneak a badger into their breadbox.

"Really? How so?" John put his laptop on the coffee table beside him and turned to face Sherlock better.

"Well," he began, "my parents raised me to be a gentleman" John snorted but he ignored him, "I was told to never take advantage of somebody drunk, always be polite"- another snigger from John-"yes, yes I know, it's all really funny isn't it? And i was told to never swear. However," he continued, "I've noticed with alarming frequency that, well, things just slip out. I've realized just how often you swear as well" after a few seconds of contemplation, John sighed and replied wearily,

"I'm afraid I don't agree with you Sherlock," he said, "my language isn't any worse than Lestrade's or Stamford's, and you hang around them heaps. In fact, I'd say Lestrade is worse." John chuckled. Sherlock huffed out a retort and John went back to his laptop, typing nauseatingly slowly. He was nearly finished his last few sentences, and God was he looking forward to a cup of tea. The sounds of traffic outside buzzed through the quiet flat for a few minutes before-

"Sh*t! F*ck NO! God Dammit!"

John groaned out in intense frustration and Sherlock glanced over at John casually.

"Something wrong?" Sherlock asked innocently.

"Oh, F*ck off, Sherlock!" John spat, "My laptop shut down and I've lost my whole blog! And I was just about to post it too!" Sherlock feigned a look of shock.

"You kiss your mother with that mouth?" A hardly suppressed snigger slid across Sherlock's face, but he remained silent. John stood up curtly and smacked Sherlock on the back of the head as he walked past. Sherlock yelped, massaging his head.

"My mouth is just fine, you insufferable git", he said as he flicked on the kettle. He wandered over to the fridge and opened it up. Nothing was stopping him from having a cup of tea anywa-

"Are you F*CKING kidding me Sherlock?! We're out of bloody milk AGAIN?!"

Sherlock's laughter rang throughout the flat.

AN: I'm considering making a Part 2 of this where we see one of the time's Sherlock swears in public without meaning too! What do you guys think, should I do it? Constructive criticism is greatly appreciated! I wanna know how I did and how I could improve! Reviews are Nutella for me!