Perhaps oddly, for someone whose life has been full of swords, it was a phrase I had never heard before Clarion. (Perhaps not so odd. The secondary point of fencing is not to get hit. Leaning into the blade is pretty much discouraged.)
To lean into the blade. For a writer, it means to step into the discomfort. To be brave. To take the emotional risk and actually put something of yourself on the page. It doesn't necessarily mean to be confessional in your writing, but it does mean to be honest. To strip away the artifice and leave the naked art. I imagine that this is something all artists strive for, even if the terminology is different.
As the phrase suggests, it hurts. I don't believe my job as an artist is to offer comfort, I believe that my job is to do the exact opposite. I want to cause you, my reader, to think in a way that is uncomfortable for you, to ask you to see things differently, to consider alternate possibilities. My job is not to give you the happy ending, it is to give you the right one.
Even if I have to bleed to do it.