Now that the title has your attention, read on.
This is not going to be suggestive writing advice about working with no clothes on. Plenty of people do that. However you write, if it works for you, then great.
When I refer to naked writing, I refer to leaving the filters completely off. Free-writing is meant to be an all-out sprint of spirited working away with words. It’s writing/typing freely.
The focus should be on writing first and editing later if needed. My tendency to want to revise constantly stops me from fairly working an all-out free write. So the answer to this should be to write naked. Have the words out there completely with no revisions at all until such a time when the free-write is completed. Revisions are comparable to clothing being put on to the words and sentences. You need to dress them up to make it all complete.
The words have to start somewhere. Work them out. Leave them naked until it’s time to have them get dressed.