It was just one swift movement that changed the entire dynamic of their relationship. Something that happened purely by accident, on one of his impulsive whims. Without giving it much thought, and to exhaust a question that was eating at him, Sherlock had kissed John.
John had been gone all day, off at work or something else as unimportant to Sherlock, which left said detective to be alone with his thoughts. They had just solved a case, and surprisingly Sherlock hadn't felt his usual desperate itch for another one. This was due to John's strange behavior ever since he returned from his sister's a few days earlier. Sherlock couldn't put his finger on it, but the way Jon carried himself, the way he looked at him, and the way they communicated had slightly shifted from before he left.
After going through his phone he ruled out any type of drug use or new girlfriend. Plus, he would have been able to read that in an instant. No, this was something about John that changed. He didn't become religious or join a gym, that he could tell, and he obviously hadn't changed occupations. He wasn't in the least bit a fan of not knowing something about his only friend, so he took the time to investigate. He decided to start investigating in John's bedroom, something he normally wouldn't stoop to but his curiosity overcame his manners.
He scanned the room with his eyes, making streams of deductions as he went. Nothing out of the usual, nothing that didn't fit. Checking the suitcase was fruitless, so he tried all the pockets of pants or jackets he could. Still, nothing. As he was about to give up a colorful piece of paper caught his eye, hidden under a book on the dresser next to the bed. He crossed the room and picked it up.
It was a pamphlet for a gay pride club in his sister's town. It was titled "Can't Think Straight" and had a subtitle of "So you think you're gay…" beneath it. After scanning the content and recognizing some of the suggestions in coping with a crush in John's attitudes, Sherlock immediately put the flyer back where he found it, and walked directly out of the room. He feared he had just seen some part of John he wasn't supposed to. This clearly wasn't something John would own unless he had sought it out. His sister could have just given it to him, but he would have thrown it away if it meant nothing. That added to the fact that it was semi-hidden but well-read, gave Sherlock a feeling this had everything to do with John's change of behavior. After leaving John room, he went directly into the living room where he sat down in an arm chair and didn't move for the next few hours.
John came home around six, bustling through the door, carrying grocery bags. He gave Sherlock a nod as a greeting and carried the load into the kitchen. Sherlock followed him with his eyes, saying nothing. He could hear him making noise in the other room, unloading the food.
"Did you clear out the fridge, then? Like I asked?" John called. A second later, after Sherlock heard the fridge open then close, "Oh. Alright then, it's fine. You must have been busy." He said simply. That was the last straw. Sherlock stood up immediately and stalked into the kitchen.
"Would you stop that!" he ordered, making John freeze, holding a jar of peanut butter midair.
"Stop what?" he asked puzzled.
"That whole polite bullocks you've been spewing," he growled as he walked around the counter angrily.
"Sherlock I don't know what-"
"Oh yes you do. I haven't done a thing you've asked me to do since you've returned from your sister's and every time its 'fine' or 'I'm sure you were busy.' You haven't gotten mad at me all week! And just now you didn't say anything about me not helping to carry in the food, or clean out the refrigerator. Just knock it off John, killing with kindness doesn't suit you." he heatedly explained.
John stood wide eyed, scrambling for words, unsure how to react to Sherlock's little outburst. Until, something he said caught his attention.
"Killing with kindness…? Have you been in my room?" he asked agitatedly. That was one of the phrases on the pamphlet Harry had insisted he took home with him.
Instead of answering, in the heat of the argument, Sherlock swooped his face down to John's and kissed him. He was forceful at first, but slowly eased up. John had dropped the unopened jar on the floor in surprise, but did nothing with his hands except lay them on Sherlock's chest as if to restrain him. They stumbled back, so that John was pinned between the counter and Sherlock. The kiss was a short-lived flurry of passion, and once John had slowly pulled out of the shock, he pushed against Sherlock to drag his face away. Sherlock's eyes immediately began analyzing John's facial reactions.
"What," he began, his eyes on the floor, "was that?" he asked finally, as his heart rate began to settle.
Sherlock smirked, "an experiment." He began to back off, intending to return to the living room for further analysis, but John stopped him. He instinctively grabbed Sherlock's hand, and pulled him back close to him. Sherlock allowed this bit of manipulation, and let John tangle his hands into the hair and pull him in. Their mouths were close again, and he was surprised how much he enjoyed the feel of John so close. They both were still, listening to each other breath.
"You did go in my room," he breathed, then closed the distance between them. This kiss was more careful, thought out. John's experience put him in control, as he gently dragged his lips across Sherlock's. John's pent up passion for the other man melted out of him and the softness quickly was gaining heat. Sherlock raised his hand to John's neck, as their lips wrestled for dominance. He was surprised how easily all his fast moving, painfully loud thoughts halted into silence as he absorbed the sensation of their bodies being so close. John slipped his tongue along the edge of Sherlock's lip causing a slight hum from Sherlock of surprise and pleasure. Sherlock let instinct take over and pushed further into the kiss, sliding his arm to the base of John's back to pin their hips closer together.
Neither of them were thinking and nothing felt off, it was as if they had both known this would happen, while at the same time could never guess how right it would feel. They leaned against the counter, exploring each other's mouths for some time, until both men needed air. They pulled apart, breathing heavy and resting foreheads against each other. Grins creeped onto both their faces, and as Sherlock leaded down for a round two, John raised his hand to block the kiss with a tut.
"Clean the fridge," he ordered, and walked away pointedly, leaving a very confused Sherlock alone in the kitchen.