The most common and most likely answer to this crossword clue is the 3 plus 3 plus 4 letter word HIT THE DECK
I've seen this crossword clue in The Times
H
I
T
T
H
E
D
E
C
K
More clues leading to the result HIT THE DECK
Buddy explains!
The straight part
We know that "fall" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fall = hit the deck.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.