keep the ball rolling

Example: “Ask another question to keep the ball rolling.”

Origin: Descends from an earlier British phrase, "keep the ball up," used figuratively by the philosopher Jeremy Bentham as early as 1781 to describe keeping a conversation going, drawing on the literal image of keeping a ball aloft rather than letting it drop. The rolling version most plausibly grew out of everyday ball games, where getting a ball rolling to start play is a simple, universal action that extended naturally into figurative language for starting or sustaining any activity by the late 1700s. The specific American phrasing "keep the ball rolling" became genuinely widespread thanks to the 1840 US presidential campaign, during which supporters pushed enormous ten-foot tin-and-leather balls from town to town between rallies, chanting the phrase as a literal, physical slogan — a vivid publicity stunt that popularized an already-existing idiom rather than inventing a new one.