Hearing it said that he looked alive and beautiful made Sherlock blush. He had not allowed himself to feel that way for a very long time and when it did happen, (also known as the moment John came in his life) he wasn't aware of it any more. So hearing John saying it out loud made him shine even more. He lay his head on John's chest, his hand absent mindedly fumbling with the folds of John's shirt near his elbow.
"I love it too when you are at work. Not the work at the clinic. I mean the chasing after criminals. You look most alive when we are running, your brow is wet of sweat and your lips parted of panting. You have that glint in your eyes, that I only normally see during sex. Then you are also very alive, I might say."
Sherlock heaved a happy sigh, feeling John's chest bobbing up as John inhaled with him. Sherlock didn't feel sleepy or restful at all, as his fingers showed. His feet was tapping unheard rhythms in the air. Not long after he had laid his head down, he got up again and looked at John.
"We have still-" He looked at his watch. "Two hours and forty minutes until sunset and I am becoming bored. You are lucky, because I'm feeling generous now the case goes well, so you can decide what we are going to do meanwhile."