This is just a short one-shot, written a long while back, but I still wanted to share it with you all. :-)
John came home after a hard day's work at the clinic. He stomped up the stairs of 221B Baker Street, threw his bag on the floor of the apartment and slouched down in his armchair.
"Hi" he said to Sherlock, who sat in his own armchair opposite John's and was staring at nothing in particular, seemingly lost in thought. John didn't get an answer from the consulting detective, but he was used to that.
They sat in silence for a while. Sherlock kept staring endlessly into empty space, while John read the newspaper he had not been able to finish at breakfast that morning.
It wasn't until Sherlock reached for the teacup on the table in front of him, that John noticed something was amiss. Sherlock reached with his left hand. He never did that…
John folded the newspaper to study his friend a little better and quickly noticed a still darkening bruise on the middle finger of Sherlock's right hand, just above the knuckles.
"What is that?" John asked.
"What is what?" Sherlock answered, not breaking his staring into empty space.
"Your hand" John said, "what happened to your hand?"
"What?" Sherlock said again. He shifted his gaze to John now, frowning slightly at the doctor.
"Your hand is bruised and you're not using it. Don't tell me you haven't noticed that yet. What happened?" John asked a little impatiently now. Sherlock looked down at his right hand, which was resting on the arm of his chair.
"Oh, that" he said lightly, almost as if he were commenting on the weather.
"Yeah, that" John said sarcastically.
"I punched Mycroft in the face" Sherlock replied bluntly.
John felt as if he could fall off the couch in amazement. This was certainly the last answer that he had expected to get.
"And why would you do that?" John asked incredulously.
Sherlock shrugged. "He had it coming".
"Okay, I think I can see your point there, but still…why?" John pressed on.
"He was boring me with some national security threat he wants me to have a look at" Sherlock said, "I was working on an experiment and didn't have time for such nonsense".
"Usually when Mycroft brings a case to you it is no nonsense, and national security is not boring" John said defensively.
"Yes, it is" Sherlock replied quickly, "whatever he brings to me is not worth his own time, therefore must be boring".
"Alright… and punching Mycroft is your solution to that?" John smiled faintly and actually had to suppress a chuckle when an image of Mycroft sporting a bloody nose popped into his mind.
"It worked" Sherlock retorted a little annoyed.
John looked over at Sherlock again and found the consulting detective looking back at him with a mischievous sideways glance. A smirk played on his lips. Suddenly the two of them laughed out loud at this ridiculous situation.
"But, honestly, Sherlock, I do need to take a look at your hand" John said after the worst of their laughing fit had subsided.
"I'm fine" Sherlock answered, "it'll pass".
"No, really, Sherlock" John said a little more sternly now.
Without waiting for Sherlock to protest again, John walked over to him and wrapped his hand around the detective's wrist. Sherlock tried to pull back, but John held on stubbornly.
"Sherlock" John said as if he were talking to a naughty child. Sherlock stared angrily at the doctor for a little.
"Or are you going to punch me too?" John said with a smile. Sherlock snorted softly and finally abandoned his 'struggle'. He rested his hand on the arm of the chair again and John immediately inched closer to have a look at it.
The bruise on Sherlock's middle finger was still darkening and the entire finger was clearly swollen. John carefully pushed around the bruise, until he found a spot that made Sherlock inhale sharply and pull his hand away.
"Sorry" John said for hurting his friend, "can you move it?" Sherlock tried to wiggle the finger and was able to move it a little, but it clearly was painful and he quickly ceased his attempt.
"Yeah, I feared that" John concluded with a hefty sigh, "you broke it".
"Hm?" Sherlock had drifted off into thoughts again.
"You broke your finger" John repeated.
"Really?" Sherlock reacted a little surprised, "well, that's a first". John simply looked questioningly at him.
"I punched Mycroft before, many times actually" the consulting detective explained, "but this is the first time his big nose actually broke any of my bones".
"Well, first times for everything" John said jokingly. And together they laughed out loud again.