What is "to screw in"

Screw \Screw\, v. t. [imp. & p. p. Screwed; p. pr. & vb. n. Screwing.]

1. To turn, as a screw; to apply a screw to; to press, fasten, or make firm, by means of a screw or screws; as, to screw a lock on a door; to screw a press.

2. To force; to squeeze; to press, as by screws.

   But screw your courage to the sticking place, And we'll not fail.
   --Shak.

3. Hence: To practice extortion upon; to oppress by unreasonable or extortionate exactions.

   Our country landlords, by unmeasurable screwing and racking their tenants, have already reduced the miserable people to a worse condition than the peasants in France.
   --swift.

4. To twist; to distort; as, to screw his visage.

   He screwed his face into a hardened smile.
   --Dryden.

5. To examine rigidly, as a student; to subject to a severe examination. [Cant, American Colleges] To screw out, to press out; to extort. To screw up,

   1. to force; to bring by violent pressure.
      --Howell.

   2. to damage by unskillful effort; to bungle; to botch; to mess up.

   3. [intrans] to fail by unskillful effort, usu. causing unpleasant consequences. To screw in, to force in by turning or twisting. Screw around

      1. to act aimlessly or unproductively.

      2. screw around with, to operate or make changes on (a machine or device) without expert knowledge; to fiddle with.

      3. [Colloq.]commit adultery; to be sexually promiscuous.