Do you hyphenate half-in half-out? He was half-in half-out. (of the window). Or half in, half out? Sheesh, nothing coming up on google. Any ideas/help please?
I see no reason for hyphens. Then, again, I see no reason for many apostrophes in today's names, but there they are. (Saw one recently, Rickey la' Davis--really?!)
No hyphens, because "half in" and "half out" aren't words. Hyphens connect the parts of a compound word. The stress on the last part of each, "in" and "out", is a clue that these are phrases, not words. Compound words usually have stress on the first part of the compound.
You could add a comma after "half in" to clarify the structure, if you wanted.