敲小鼓

qiāoxiǎogǔ ㄑㄧㄠ ㄒㄧㄠˇ ㄍㄨˇ

    • to be nervous and uneasy
    • to have one's heart pounding

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
beat a little drum
Meaning
One's heart pounds from nervousness or unease. Used of anxious waiting.

Sources