There are a few different kinds of "organizing" within my system. Some of them are entangled in the "processing" step and some aren't.
Some inbox items drop directly into appropriate spots in my system. They represent phone calls I need to make, materials I need to review, whatever. So "organizing" simply means putting them on the appropriate list.
Some inbox items add a lot of information at once to my system. A meeting, a conference, or the end of a project might generate a pile of materials for which the next action is "organize."
Some inbox items represent new projects, for which the next action might be to plan my approach, work out a timeline, etc. Again, "processing" generates an "organize" next action.
And then there's the daily organization step that happens so quickly that it isn't really noticed as such: look over my lists and decide what to do and in which order.