Like many other states, California has a seat belt law. Many cars have awkward and annoyingly difficult to use seat belts. As a result some people have taken to just holding the seat belt across their chests, not really fastening it, when just taking a quick drive to the corner market. Thus the "California click". That way it looks like it's fastened in case a cop should see you. See Califoria stop.
Don't worry about the damn seat belt, just do a California click!