What does "thrusting" mean?

Thrusting: (Dairies) (a) The act of squeezing curd with the hand, to expel the whey. (b) pl. The white whey, or that which is last pressed out of the curd by the hand, and of which butter is sometimes made. [Written also thrutchthings.] [Prov. Eng.] Thrusting screw, the screw of a screw press, as for pressing curd in making cheese. [R.]