While listening to the cricket on the radio the other day, I heard the commentator say “The English [cricketers] are keeping their worm up”.
The worm refers to a graph showing the run-rate (number of runs scored per over, where an over is six balls bowled (pitched)).
Continuing at a constant rate will result in a “flat worm”, but there’s normally an increase in scoring rate near the end of the innings, so the worm creeps up.

The term is also used when a studio audience is asked to reflect their opinions of a political debate in real time. The worm can move towards one candidate or the other depending on the audience’s net impressions of their performance.