For anyone not aware, fandom_stocking is a holiday event. Full rules can be seen at the sign-up post, but the basic run-down is that you sign up, giving a list of your likes and dislikes, at which point the mod makes a community post just for you. Comments on it are screened until January 6th, so people have from whenever the stocking is posted until then to leave you fic, icons, words of good cheer, doodles, whatever the hell.
Just like how wrapped presents accumulate slowly under a tree but then are opened all at once on Christmas, you gain e-treats that are hidden until you see them all at once on Epiphany. Cool idea, right?