Sometimes John runs out of the flat and Sherlock finds not having John there really bothers him. Sometimes it's the Three Garridebs scenario. And sometimes, apparently, it's absolutely hilarious auto-correct failures on the phone that puts sex on Sherlock's brain, to the point that the inevitable becomes the did-we-really-just-do-that?
Exhibit A in the latter category: What He Wrote, by fitofpique.
It's the quiet moments that really make this work, the subtleties of Sherlock's reaction – confusion, amusement, frustration. It's really very cute, particularly if you like to imagine Sherlock being a bit thick-headed and out of his element where matters of the heart are concerned. It's the "gay baby penguin" syndrome, as they put it over on Tumblr – but not in a way that makes him seem incapable or immature. And the sex scene that you can imagine it's driving toward is tastefully done, really in-character for how she writes these characters.
Really, it's a delightful mix of domesticity and humor and sexual tension and then relief of the same. I highly recommend it.