Late_Bloomer: I typically do the Mt. Dew can comparison-- if it's thicker than a Mt. Dew can, you're safe in saying it's big. In my group of friends, six of us are "large" in the length department, and of us, 3 of us are thicker than said can.

Oh and nothin beats having a cold can of Mt. Dew on your cock than drinking a cold can of Mt. Dew after it has just recently been on your cock. :D