Awake
Sherlock is awake, analyzing things. This is not unusual for him at all. Even as the clock ticks the morning away towards dawn, it is not abnormal for him to be awake, thinking, mulling, alone on the couch.
But it's different this time. Because he normally holds his hands, palms pressed together, beneath his chin, tonight, he has both of his hands towards the center of his chest, rubbing the thumb of his left hand across the palm of his right and thinking about earlier that night.
About how he'd put out his hand and John took it. He did not grab John. No, no, he put out his hand, palm up, an offering, and John took it. Without hesitation, without question, without... anything, but obedience, and, something else.
Something under it. Something that had caused John to continue to hold on after they were out of danger. After they were out in the parking lot, away from Moriarty and the pool and the bomb, and for a moment (Sherlock remembers this because he's Sherlock Holmes), John actually squeezed his hand tighter once they were out of danger.
Sherlock clasps his right hand fully in his left as a memory of what happened next almost escapes him (wants to escape him), but ever the analyst, ever the observer, ever the detective, Sherlock does not let it, no matter how hard his subconscious tries to push it away.
Sherlock squeezed back.
"Well that is... interesting," he said, aloud to the darkness, still rubbing his hand, as though it'd betrayed him somehow.
Then rolled over onto his side, facing the wall and slept on that couch until John woke him in morning with a black cup of coffee - two sugars.