Go to your profile! "edit profile" settings scroll down until you see "enable drafting"
DO IT CLICK THAT SUCKER LIKE YOU MEAN IT IT SAVES LIVES
AND MAKE SURE YOU SAVE IT!!!!1!!11!1!! scroll the rest of the way down to save the settings
now if your post doesn't go through or something, the next time you try making a post in that same thread, it should prompt you with a "you have a draft!" dialogue box, and ask if you'd like to open it and it should open the last automatically saved draft of that post so not all hope is lost if something screws up when you're about to post that perfect bio : D