Sherlock lay helplessly in his bed, violent coughs racking his body, forcing him to sit up and clutch at his chest in pain. His throat felt dry, and raw from all the coughing, and every breath he took was rasping and agonising. The sound was awful to listen to, and that sound is what John came home to that afternoon once he'd finished work.
Upon entering the flat, he heard the coughing and sighed. He removed his coat, and draped it over the sofa, before wandering to the kitchen and putting the kettle on to boil. Only once he had two steaming cups of tea in his hands did he venture into Sherlock's room. He knocked once, gently. No reply. He knocked again, slightly louder, and a feeble croak came from within, which John took as permission to enter.

"Hey." He said quietly to the form that was huddled up under the blankets. Again, he merely got a pathetic croaking sound in response. John moved over to the bed, where he sat down at the very edge, and placed the tea on the bedside table."Got a cough huh? Sounds like a nasty one too..." he murmured, resting his hand on Sherlock's shoulder. "I brought you tea. Make you feel a bit better."A cold hand emerged from under the covers and grasped John's.
"Thank you." Sherlock replied, his voice scratchy and forced.
"Hey hey, don't talk if it's painful, just sit up and drink your tea, okay?" John said, lifting his pillows and helping him sit up, one arm protectively around him. Sherlock obliged, and picked up the mug in both hands, closed his eyes and took a sip.
"There, is that better?"
He nodded.
"So what's the problem? Dry cough, aching chest, sore throat?" he asked, immediately becoming professional, as though he were simply looking after another patient.
Sherlock nodded again.
"Alright, I'll be back in a second." John smiled, standing and heading out of the door and towards the bathroom, where the medicine cabinet was.

He rummaged through the cupboard for a while before he found what he needed. Cough medicine, for 'dry, tickly coughs'. Highly inaccurate way of describing it, he thought to himself. Less 'tickly', more agonisingly painful. In any case, he took the bottle through to the bedroom, where he found Sherlock wandering around aimlessly.

"Sherlock, what are you doing?" he asked kindly.
"Walking." He rasped.
"Come on, get back into bed." John smiled, guiding him in the right direction.
"I feel better John." He protested. "Really, I feel fine!"
John chuckled. "Sherlock. Bed."
"But-"
"Bed!"

Sherlock huffed in annoyance, and shuffled over to his bed, grumbling under his breath.
"Right, now sit there and take this medicine alright? It'll soothe your throat and it should stop your chest from hurting so much."
Sherlock pursed his lips like a petulant child and refused.
"Now come on, grow up and stop acting like an infant."
"But I don't like medicine, it tastes horrible..." he complained. John frowned and held out a spoonful of cough syrup. Sherlock remained with his mouth firmly shut. John gave him a look which said that if he did not do as he was told this instant, there would be consequences. Sherlock rolled his eyes and gave in.

"That's more like it." John smiled. Sherlock pulled a ridiculous face as he swallowed the medicine, causing John to chuckle.
"Now, you lie down and rest for a bit and-"
"John." Sherlock interrupted, causing him to cough violently for a minute, before recovering and continuing to speak. "I do not intend to spend the entire day bed-ridden."
John half-smiled when he heard this. "No, I should think not. Come on." He said, standing up. "I've got some old Doctor Who box sets we can watch this afternoon."
Sherlock's eyes lit up. He didn't usually get excited about TV programmes, but he made an exception for Doctor Who. Mostly because it was John's favourite show, so he made a particular effort to like it, which he found, led to genuine enjoyment of it.

He was out of the door and sitting on the sofa in seconds, with John following behind, laughing softly to himself. He took out the DVDs, put one into the DVD player and settled down on the sofa next to Sherlock, who was having another coughing fit. John put a hand gently on Sherlock's back.
"You okay?" he asked, concerned.
"Yep..." he wheezed, between coughs. "Just..." cough cough "...fine"
"I'm sorry, that sounds horribly painful." He murmured sympathetically.
"I'm alright. Just... play the DVD."
John did so, and they sat for almost half an hour, in absolute silence, only broken on occasion by coughs. Sherlock didn't even comment once on the impossibility of certain events. By the time the episode had ended, he'd, without realising it, manoeuvred himself on the sofa, so that he was pressed right against John, his head resting on his shoulder.

John looked down at their current position and smiled inwardly. He brought one hand up to rest on Sherlock's head, his fingers playing with the mop of dark brown curls.
"You feeling any better?"
"Much." Sherlock made no attempt to stop John's comforting touch. They both realised that sitting together like this was not a thing that flatmates, or even friends did, and yet it was a thing they did all the time. Neither one knew what that made them, nor honestly did either one care. John leant down to press a soft kiss on top of Sherlock's head.
"Good." He exhaled slowly. "Honestly, I don't know what you'd do without me to look after you." He joked.
"I managed before. But now that I have you to look after me, there's no way I'm letting you leave." He chuckled, then paused.
"Thank you." He added quietly, seriously. "Thank you for everything."
"You don't need to thank me."

Sherlock nodded, and they fell silent once more, for they both knew there was nothing else that needed to be said. Sherlock needed John, and John needed Sherlock. End of discussion. That was how they liked it, and they were happy, and nothing else mattered.