on the button
精确无误、准确到位
口语·强调时间或动作精确无误
英文释义
at exactly the right time or in exactly the right way
例句
He arrived at 3 o'clock on the button, just as promised.
典故来源
可能源自拳击比赛中击中按钮（button）即得分，或与精确计时器按钮有关，强调准确性。