The things you find on the internet...
Lingam gnosis is a way of finding out about somebody's character traits by studying a part of their body. Much like palm reading, only in this case the body part to study is the penis.
According to the writer of the site (appropriately named Yoni Appassionata) penises can be divided into four categories: earth, fire, water and air, based on what they look like. (If yours looks like a potato, rejoice, you're an earth type!)
Each type signifies specific personality traits for its owner: earth types are simplistic and rather stupid, fire types are aggressive, assertive and controlling (but great in bed), water types are nurturing and feminine (can anyone explain to me how a penis can look feminine?) and air types are unfaithful and fickle, but imaginative and intelligent.
You can read all this and more, and even find some case studies with pictures, at
Personally I'd advise anyone to find out things like these by way of conversation before you get into close encounters with someone's private parts... but I'm kind of old-fashioned that way.