This is not a place for discussion or deep thoughts. While I have added a few other excited utterances and a plot bunny below the cut, this is primarily for the sentence I thought it would be indecorous to yell in a thin-walled apartment.
IRENE IS A LESBIAN DOMINATRIX!
Everything about this episode was perfect. The fake-out with the cliffhanger. The way they showed time passing. IRENE. The way it was all about Sherlock's relationships with other people. The way it was hilarious. The "I'm not gay"/"I am" conversation between John and Irene where the unsaid "and we're both in love with Sherlock" is so close to the surface that it's barely subtext. The scene with Sherlock and Mycroft and the cigarette. "The Iceman and The Virgin." Sherlock at Buckingham palace wearing only a sheet. The way Sherlock absolutely and completely loves Mrs. Hudson.
I rewatched the first season last week, and it left me wanting Molly/Sherlock awkward dating, and this episode did nothing to dispel that. I couldn't think of a hook, but now there is one: he's trying to understand dating, and also Irene is going to have her dalliances so he can too. (Perhaps Irene shows up and sort of approves.) I was thinking that Sherlock should be a virgin in that story, and that would still totally work. (Maybe he doesn't sleep with either Irene or Molly. I don't know how that would eventually be resolved, though.)