keep shirt on

keep one's shirt on

 and keep one's pants on
Fig. to be patient. Wait a minute! Keep your shirt on! Keep your pants on! I'll be with you in a minute.
See also: keep, on, shirt

keep (one's) shirt on

Slang
To remain calm or patient: The plane doesn't land for another hour, so keep your shirt on.
See also: keep, on, shirt