At another's mercy (4,1,6)
I believe the answer is:
over a barrel
(Other definitions for over a barrel that I've seen before include "forty-odd gallons of beer?" , "In a mess" , "forty gallons or so?" , "Unable to manoeuvre" .)
I believe the answer is:
over a barrel
(Other definitions for over a barrel that I've seen before include "forty-odd gallons of beer?" , "In a mess" , "forty gallons or so?" , "Unable to manoeuvre" .)