This means a person who wishes so badly to be japanese, but only watch's anime, think about being a harajuku girl/boy, and that japan is the best.
But, if you watch anime, are realated to someone japanese, learnt how to speak enough to be polite and talk in a convo, learnt the history, dress which ever jap style you like (remembering that harajuku is not everyday) and are proud of what you are, Then you are not a wapanese.
Person 1= is from one culture or 2, but not from japan, obssessed with japan, only knows crappy words from anime translations and eats jap food and think they are japanese are a wapanese.
Person 2= comes from one or 2 backgrounds and has one japanese person in the family or more, watches aniem, helps, know the history, speaks 5/10, draws, dresses japanese. Is not a wapanese.
Why? because person 2 is realted to someone jap. Trust me there are people like this.