To clench one's fists and rub one's palms, indicating eagerness or readiness to act, often aggressively, or to express impatience.
比赛前，队员们都在场边擦拳磨掌，等待上场机会。
Before the game, the team members were clenching their fists and rubbing their palms on the sidelines, eagerly awaiting their chance to play.
Next Idiom