This one fits shortly after Mycroft leaves (following Rohypnol).
Sherlock put his violin back down.
"So, your head's feeling better then?" John said.
"No. I need complete quiet. Don't talk."
John smiled. He took his newspaper back and settled down on the sofa. Sherlock sat on his armchair and sulked at the fireplace.
"One thing does confuse me a little bit," John said.
"You couldn't do that thing you do with Irene Adler," John said.
"That thing you do where you work out everything you can about a person," John went on. "I knew you were confused, because you looked confused. It's a look I've not seen many times, so it jarred a bit. Plus, then you did that thing you do with me, and I know what that looks like, because I've seen it many, many times."
"Yes. Good. Shut up."
"By the way, I wasn't out with Mike. You confused yourself by forgetting that I have more than one friend."
"You only have one drinking friend. I don't drink."
John smiled. "I have more than one drinking friend, though we're escaping from the point a bit. You couldn't work out anything about Irene Adler."
"The woman had no clothes on. It makes my job a bit more difficult."
John smiled. He walked over to the armchairs and sat down with Sherlock.
"You honestly couldn't get anything? Other than her measurements, I mean?"
"You see it strikes me as odd," John said, "because you're obviously better at this than I am, but I could tell she was in her thirties, hadn't ever been pregnant, certainly hasn't ever breastfed, and still has her appendix intact. Even from a non-medical perspective, I could see that she was perfectly comfortable in her own skin, and she spends a lot of time taking care of that skin, though she does like to indulge in foreign holidays and doesn't use quite enough sun-block when she's sunbathing. She has an excellent skincare regime other than that. Someone washes her, regularly, possibly on a daily basis. She has expensive taste in make-up and knows how to highlight her assets even when she's not wearing any clothes, which is a cleverer skill than you'd think. Oh, and despite that profession, she keeps her clients at a great distance. She doesn't have regular penetrative sex."
"Is there any other…" Sherlock said, and then quickly turned the question into a cough and blushed.
John let it pass.
"So how long did it take you to work all of that out?" Sherlock asked.
"Oh, not long. I was awake quite a lot of the night, but it gave me something to think about."
"And you've been waiting patiently to show off your superior knowledge of naked woman?"
"Yeah. It's a bit interesting being you, isn't it?"
"I'll admit to a certain pleasure in it, yes."
"I'll not point out that you could have worked most of that out from her choice of career then," Sherlock snapped. "I'm going back to bed."
He stomped into his room and slammed the door after him.