jemandem die Daumenschrauben anlegen
to put the thumbscrews on someone; to pressure someone hard
Origin
The thumbscrew was an iron instrument of torture used by late-medieval and early-modern justice to force confessions in the name of "finding the truth".
Building blocks
Words in this expression
Examples
Erst als ihm die Daumenschrauben anlegte, rückte er mit der .
Only when the pressure was really put on him did he come out with the truth.