John got out of the cab, keeping the door open so that Sherlock could climb out after him. It couldn't have been later than nine that night, but they had been gone for several hours and spots of blood and chemicals stained their shirts as they trudged up the icy sidewalk and into 221B.
Sherlock threw his coat lazily onto the table as John flopped onto the couch, exhausted, and flicked on the television set. Sherlock stood hesitantly in front of John before deciding to simply curl up on his legs with the cup of tea that he now held in his hands. John groaned, legs pinned under Sherlock's weight as he tried to remove them from out of under him. John sighed, but returned his attention to the images on the screen for a split second before realizing that Sherlock had moved, laying fully on top of him. "What are you doing?" John asked hesitantly.
"Just an experiment," Sherlock said, nuzzling his nose against John's cheek, so that the doctor would turn his head.
John let out a strange exclamation as he whipped his head around, his lips touching Sherlock's for a split second. "What are you doing?!" he asked again, flustered from the light touch, almost disgusted that he enjoyed it. Sherlock was his friend, that was it. Why was he climbing on top of him and kissing him, not for science, that was a deduction that John could make.
Sherlock chuckled, pleased to see that John enjoyed it, just like he knew he would from countless hours of observation. "It's just a little science experiment," he said. It wasn't a lie, to him this was a little experiment in human interaction and relationships.
He noted the pink flush creeping onto John's cheeks and dilation of his pupils along with an increase in heart-rate. He took the subconscious signs as a green light and continued, resting his lips awkwardly on John's again. This time, the doctor didn't protest; taking the kiss as a gift and teaching Sherlock how to gracefully move his lips in tandem with another's.
After what could have been anywhere from a couple seconds to a few minutes, Sherlock sighed as he detached himself and explored John's eyes with his own. He smiled lightly, then returned to his seat on John's legs as though nothing had happened.
"What... What was that, Sherlock?" John asked, craning his neck so that he could better see his flatmate.
"It was a kiss, John, don't be stupid," Sherlock replied flatly, staring at the television, "It was nice, wasn't it?"
John cleared his throat, "Well, yes. I mean, it was a kiss, that was obvious. I mean not that it wasn't nice... Or anything. Just, why?"
Sherlock shrugged in response, "I told you, an experiment."
John scoffed, "That was not an experiment," he said, pausing to tug his legs forcefully from underneath Sherlock and sit upright beside him.
"Yes, it was," he asserted.
John sighed with resignation, knowing that it was useless to try and argue with him, "Fine, what did you gain from this 'experiment'?"
Sherlock cracked a wide, toothy grin before explaining in full detail what he had learned. First, he had learned that John Watson had a crush, which he had already established months before, but this episode had solidified his theory. Second, he had learned that Sherlock Holmes had a crush, which secretly startled the detective himself. Third, he learned that John had kissed upwards of fifteen women in his lifetime, and that this was his first man. And the last thing Sherlock decided to share was he learned that although John thought it was awkward, considering it had been Sherlock's first time, that it was one of the single most adorable things he had ever witnessed.
John flushed gently at the wordy deduction, only giving a coy smile and a light nod to the analysis before curling into Sherlock's side. Sherlock simply stared curiously at the man who wad pressed against his arm for several seconds before wrapping his arm around him and burying his face in the dirty blonde hair. "So does this mean...?" Sherlock asked.
"I guess so," John answered.