What does it mean Black Guys have Swagger?

Keeping it short me and a friend ran into girls(both white) who said they only into black guys. You meet girls online too for example who say same thing. So from the reasons given I got curious and googled. One thing some of them mentioned black guys have swagger.

What exactly is swagger, and why is it only associated with black guys. What does it mean they just have something, the way they talk and walk, how they make us feel. If they mean confidence do other guys not have confidence? What is swagger exactly? Can girls elaborate on it maybe example or two.

From dictionary.com

Swagger

Verb:Walk or behave in a very confident and typically arrogant or aggressive way: "he swaggered along the corridor"

Noun: A very confident and typically arrogant or aggressive gait or manner.

Urban dictionary has several entires, most of which are the same or variants of.

http://www.urbandictionary.com/define.php?term=swagger