If we are thinking of the same thing, clicking (tapping) and holding on the red circle will bring up a small screen that is zoomed in on where you are touching.
This allows you to carefully move the cursor where you are trying to edit. For instance, if you wanted to remove a letter 5 words back, instead of attempting to tap right to where you want to delete the letter, you can tap once, then hold on the red circle for a little more accuracy