To hide, prostrate yourself in the ditch? (3,3)
I believe the answer is:
lie low
'to hide' is the definition.
(lying low is a kind of hiding)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for lie low that I've seen before include "Conceal oneself, don't be conspicuous" , "Absent oneself from social contact (for a period)" , "Go to ground" , "Keep hidden" , "Remain unobtrusive - in prone posture?" .)