Dude, you're going to get hugely exaggerated guess-timations from there guys because they are (no offense) very fixated on extra large dongs. Would I be REALLY off if I guessed that most of you preferred watching adult entertainment with very large dudes? Like Lex, Erik Everhard, Mandingo, Jack Napier, etc...
So I think most guys' perspective will be VERY skewed. They'll probably guess about 8-9 inches. But I say the average mainstream adult entertainment dick is about 6.5-7.5 inches long. They do a LOT of image distortion and camera angle tricks to make dicks look bigger.