John had been in bed less than five minutes when he saw the shadow at the base of his door. It was followed by a... timid... knock. Since when did Sherlock knock timidly? If there was a case, the man always burst through the door and tossed the doctor's coat at him, shouting, "The game is on, John!"
"Sherlock?" the doctor called into the darkness, "Is everything alright?"
Sherlock, heart pounding, cracked the door open and stepped into the doctor's room. "I don't know. Perhaps. It could be. It might not." But he intended to find out tonight one way or the other.
The detective's words were about as clear as mud to John. "I don't understand. Look, why don't you have a seat and tell me what's happened?" He moved over in the bed to make room for Sherlock to sit down. As he did so, a thought occurred to him - maybe something had happened to Mycroft. Maybe he was missing or something. That would explain the detective's odd answer and behaviour.
Sherlock sat on the edge of the bed, as close to the doctor as he could manage. His heart was beating fast at the prospect of what he was about to do. Silently, he berated himself. He could chase down killers. Why should this be so difficult? The detective braced himself, then he surged forward and kissed John full on the lips.
A moment passed, two, three, in which nothing happened, then the doctor shoved Sherlock roughly away. "What. The fuck?!" Maybe he was just plain, ordinary, idiotic John Watson, but he wouldn't be toyed with! "You don't get to do this, experiment with my emotions!"
Sherlock's heart was beating even faster, now, from confusion. Had he just been rejected or... "John. Listen to me." The detective took a deep breath, then summoned up the words that he needed to say. They felt ridiculous, but they were efficient. "I love you."
The doctor went still, then he puffed out a little laugh. "Now I know you're playing with me. You would never say those words and mean them." He wouldn't, would he? John barely dared to hope.
"Wrong." Sherlock kissed John again, hoping thereby to convince him. It seemed to work. The doctor's lips parted, and the kiss grew and deepened. What they felt for each other passed between them in the kiss.
When they broke apart, John let out a shuddering breath. "How..." He had to clear his throat. "How long?"
"I don't know. Months? Years? Forever?"
The doctor pulled Sherlock down in the bed so they were laying next to one another. "God, me too. Me too. I love you, Sherlock Holmes."