I have a rly srs question though.
Did Sherlock leave the room to put his clothes on, or did he just drop his sheet in the middle of Buckingham Palace like yes your majesty this is my dick, wanna fight about it?
Judging by that look on his face, I’m sure he compromised by putting his clothes on right there in that room, just to irritate Mycroft.
Not like Sherlock cares if the Queen catches a glimpse of his taint.
I bet he made John hold up the sheet as a makeshift dressing curtain.