I found this aphorism in my book of Korean aphorisms.
활을 당겨 콧물을 씻는다
hwal.eul dang.gyeo kos.mul.eul ssis.neun.da
bow-OBJ pull snot-OBJ wipe-PRES
[Someone] draws the bow [and] wipes [their] snot.
Imagine your nose is running – maybe it’s cold outside. You’re an archer. You draw your bow, and in that moment, you wipe your nose with your sleeve. I think that this refers to availing oneself of any opportunity, regardless of appearances. Or… you do what must be done in the moment.