It had been a long day and John was exhausted. First off, the surgery had been busy, second, there had been almost apocalyptic rain all day, and finally, he had left his coat at work, which held his wallet with money for a cab and his Oyster Card. All of these things added up to John stalking through the streets of London and to him being in a horrible mood by the time he arrived home.
He slams the front door and kicks off his shoes, and begins to squelch up the stairs. Dumping his bag by the door he flops onto the sofa and presses his face into the cushions, almost immediately falling asleep.
Sherlock arrives home half an hour later and leaves his umbrella in the kitchen to dry. He steps into the living room, just about to call John's name, when he finds him asleep, cuddling a cushion with his still damp hair sticking up like he'd just run his hands through it. He pauses in the middle of the room for a moment. Then, he smirks and shrugs his coat off before kneeling next to where John's head is resting.
Sound asleep.
Sherlock grins and pulls John's hair, lifting one or two sections to see if they stay where he puts them.
They do.
Sherlock chuckles quietly to himself and starts systematically moving the hair. After five minutes he smiles and stands, happy with his work. Picking up his laptop, he settles into his armchair to wait for John to wake up.
One hour later, John begins to stir, grumbling about being cold and wet. He sees Sherlock looking far too pleased with himself for John's liking. He narrows his eyes.
"What have you done?"
Sherlock blinks.
"You look guilty. What have you done?" John yawns and pulls at his jumper, pulling a face at the damp and heavy material.
"Why do you think I look guilty? I've done nothing wrong," Sherlock says smoothly, closing the laptop.
John mumbles and stands up to stretch when he glances in the mirror and snorts. Sherlock bites his lip and looks down to stop himself from laughing.
"Sherlock. Why?"
"You were asleep and wouldn't wake up. How could I not?"
John's hair is mostly flat, which is unusual, since usually after sleeping it ends up a mess, except, two flicks, one on either side of his head, resembling a pair of animal ears. He shakes his head and lets out a breath of a laugh. Sherlock stands behind him and wraps his arms around his waist, ignoring the wet clothes. He rests his nose in the back of John's hair.
John shakes his head, "I hate you."
Sherlock kisses John's neck, "no, you don't."