What does John mean when he touches Sherlock's knee and says "I don't mind?"
He means he doesn’t mind pickles on his hamburger.
Okay sorry, I’ll answer sans sarcasm! :) John’s motto has been “not gay!” since he met Sherlock. He’s never acted homophobic at all, but he gets defensive when people assume he and Sherlock are dating. In this scene he’s drunk as hell, in that murky area where you’re making conscious decisions but your drunkenness allows you to convince yourself it’s really your subconscious doing it and you actually aren’t aware of what you’re doing somehow. John’s testing the waters to see if Sherlock is interested.
So he scoots forward, conveniently loses his balance, grabs Sherlock’s knee, then looks at his hand in exaggerated surprise and says “I don’t mind.” He doesn’t mind this highly unusual and very suggestive physical contact. He says it like it’s suddenly occurred to him, like he’s never ever considered it before, and oh, hey, here it is out of the blue and it’s all fine.
Let’s look at the gifs, because…well. We don’t really need a reason, do we?
alright alright alright, scooting forward, eyes on the prize, aaaand balance
target acquired, slide forward, Captain incoming everyone lookout and THE EAGLE HAS LANDED
knee’s just for leverage getting back on the sitty thing like the slick bastard I am now I’ll just leave the hand because whatever I’m totally unaware of it and maybe that’s not even my hand the universe is weird like that man
now then, what were we talking abou—what are you looking at? OH! MY HAND! IT SEEMS TO STILL BE ON YOUR KNEE HOW UNEXPECTED.
HANDS ARE WEIRD LIKE THAT JUST LIKE THE UNIVERSE IS WEIRD AND WHO KNOWS WHY THESE THINGS HAPPEN THEY JUST DO?
a hand is just a hand a kiss is just a kiss a smile is just a smile that’s a great song amirite so who cares about hands really. “I don’t mind.”
omfg that was so smooth Operation Handlock ftfw so now what, Captain? something more unsubtler or like a little less not subtle or OH I KNOW
That’s probably my favorite thing about her character. Sometimes she knows she’s different but doesn’t particularly care. Other times after the ‘odd’ thing she does is pointed out, she still doesn’t care. Because she knows who she is, and how she got there, and nothing anyone says is going to change that.