To be legit. When something works out really well or is awesome. Used in suburban D.C. slang.
To shorten the word, 'Hattan' is a substitute. 'Hattan' is used more commonly throughout the suburbs
First Person: "Yo, dude. My parents said I could go with you tomorrow."
Second Person: "Manhattan! It's gonna be so tight man."
Second Person: "Hattan, dude! It's gonna be so tight!"