Are men who brag about the size of their penis more likely to be hiding something?

I am a 17 years old male. At school I am constantly hearing other guys in some way bragging about their penis size. I have even witnessed two kids in my class in an argument over which one of the two has a larger penis even though neither had ever seen each other's penises. The statistics in the argument were hilarious at best, numbers such as 12 inches were thrown around a lot without any real thought, of course, the whole argument being witnessed by girls in my class, I got the severely shallow feeling that the entire confrontation was an act to impress these girls. I have an average sized penis (6 inches), I rarely speak of my penis because I find the subject to be rather distasteful and rude. My question is; are men who feel the need to tell the world that they have a huge penis more likely to be insecure about their penal size than men who do not feel the need to? It appears to me as though public opinion is that of the boastful ones are bigger in penis size than the quiet ones.