The feeling of immense pressure on the inside of your skull the morning after a party.
Guy: "Holy shit, this is the worst cranial expansion I've ever had. Where the hell am I?"
Girl: " Yeah, you were pretty wasted last night, you asked me if I wanted to 'take it to the next level'. I laughed right onto the floor. That Hyundai guy who lives here wants to know where we are, too."