Oh, sh... Sherlock were dancing with his violin composition in 3s, 2 ep, it was repetition before teaching John to dance.
I get it right, yeaaah
Because we know that mrs Hudson caught them in some moment but in moment which we see in beginning of the episode she sounds surprised when say: "You were dancing". So, it is obvious that John with Sherlock learned how to dance a little later.
And his voice when he talk with mrs Hudson so soft, sad, pensive and quiet. Ah..
P. S. I was wrong because right after that scene Sherlock started dressing for the wedding. So I am confused now.











