The question you need to ask is this: was Sherlock REALLY running that experiment, or was it just a cover for watching John? After all, A SHERLOCK LOVE IS A SECRET LOVE (and a bit of a creepy love, too).
I'll be honest, though--I don't ship Sherlock and John in a sexual way. I believe that they really love each other, but for me theirs is a very deep and complex relationship that simply doesn't involve sex. You'd think they have sex, because they're intimate with each other in a way that makes it seem like they do (which is why I think it's so perfect that all the supporting characters on the show pretty consistently mistake them for a couple). But they're not. They just have this unique, incredibly close platonic relationship that no one else can quite get their heads around. IT'S SUCH PERFECTION OMFG.
Next installment: "Sherlock and John Eat at the Chinese Restaurant Down the Street"
And the installment after that: "John Defies the Captain's Orders"