hang loose = chill = relax = take it easy = don't be stressed / enjoy (life, etc.)

The shaka sign is a common greeting gesture. It is often associated with Hawaii. It consists of extending the thumb and smallest finger while keeping the three middle fingers curled, and raising the hand as in salutation with the back of the hand facing the person that is being greeted ..

hang loose>>>> its a Slang Hang Loose means: To stay calm or relaxed. To tell that every thing will be OK, Relax, Stop looking at me w/ that stern look on your face. Examples : Weekends are important: time to hang loose and take stock of things. http://www.urbandictionary.com/define.php?term=hang%20loose

When going out with a bunch of friends, hanging loose means you are not tied to them. You know where they are going, you might follow, you might not.