I saw a couple other threads in this forum about triggers, but they didn't answer my question.

I know that one can hide triggering content within a post by using something like [trigger]....[??Trigger] or something that looks like that. Obviously, I've got it wrong or that would have been hidden. Can someone please somehow in some way correct the above. I rarely write triggering content, so have forgotten how to do this. I don't want an icon. I want the empty box to appear that allows people to click it if they want to.