Turn/twist the knife British informal verb phrase
If you "turn/twist the knife", you purposely make someone's sufferings, grief even worse.
He has just been fired by his boss, and his girlfriend has turned the knife by breaking up with him.
I was given a bad grade and my friends twisted the knife by telling my parents about it.
He is boasting about getting into Yale which will twist the knife if others are rejected.
The verbs "turn" and "twist" should be conjugated according to their tense.
Derived from the fact that the act of literally twisting a knife that is still inside someone who has just been stabbed will widen the wound and make it even more painful.
Daughter: So I really want all my friends to have a great time. I was thinking it would be a good idea to have some candy out on the tables for people to snack on.
Mother: Well, if you want them to really enjoy themselves, candy is dandy but liquor is quicker.