“It's going down, I'm yelling timber.
You better move, you better dance”

Pitbull – Timber Lyrics on LyricsMode
EXPLANATION
When something falls (its going down), people will yell "timber", but she is referencing a party. You better move is telling people to get out of the way for the "falling object" but she makes it clear that she is talking about a party when she adds "you better dance".
EXPLANATION
Timber is a euphemism for erection, so when she dances people will get 'timber'. When something falls (It's going down), people will yell "timber", but she is referencing a party. You better move is telling people to get out of the way for the "falling object" but she makes it clear that she is talking about a party when she adds "you better dance".