"___ your life!" (3,2)
I believe the answer is:
not on
(Other definitions for not on that I've seen before include "Colloquially, cannot be tolerated or accepted" , "Informally, cannot be permitted or tolerated" , "Informally, can't be accepted or tolerated" , "Common expression meaning won't be entertained or tolerated" , "Modern phrase for unacceptable" .)