heart in one's mouth, have one's

have (one's) heart in (one's) mouth

To feel very nervous or anxious. I had my heart in my mouth as I waited for the ambulance to arrive.
See also: have, heart, mouth

heart in one's mouth, have one's

Be extremely frightened or anxious, as in When the plane was about to take off, my heart was in my mouth. This usage alludes to the heart beating so violently that it appears to leap upward. [Mid-1500s]
See also: have, heart