(someone's) heart is in (their) mouth

if someone's heart is in their mouth, they feel extremely nervous.

My heart was in my mouth as I walked onto the stage.

• have come a long way
• have coming out ears
• have coming out of ears
• have coming out of your ears
• have coming out your ears
• have day in court
• have dead to rights
• have designs on
• have designs on someone
• have designs on something
• have dibs on
• have dibs on something
• have done more something than has had hot dinners
• have done more something than someone has had hot dinners
• have done more than has had hot dinners
• have done more than someone has had hot dinners
• have [done/seen/had etc.] more something than has had hot dinners
• have [done/seen/had etc.] more something than someone has had hot dinners
• have [done/seen/had etc.] more than has had hot dinners
• have [done/seen/had etc.] more than someone has had hot dinners
• have down on like a ton of bricks
• have down on you like a ton of bricks
• have down pat
• have down to a fine art
• have down to a science