The question was not clearly stated. When I saw the question, "Does your cock reach your navel?", I answered "No," because I happen to know that, when I stand up straight and have my erect cock flat against my belly, it stops a bit below my navel. (You can see this in one of my gallery photos.)
I think, though, that at least some posters have been interpreting the question to mean "Can you touch your cock to a point above your navel?" On that interpretation of the question, I could say that my cock reaches just below my chest. But by the same token, just about anyone who does not have either a very short dick or a very stiff spine can say that his cock "reaches his navel." | 
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