It's about that state inbetween dreaming and being awake... when you're still trying to stay conscious. When your eyes are open and you think you're ok... and then you blink... but your eyes stay closed... and suddenly you're falling! ...and then you open your eyes and you're wide awake again! But that feeling keeps on creeping up on you, and nothing makes any sense... and then eventually you just give in to it... and you're away in dreamland.
Or is it just me who gets that?