straight leg
n.— «They possess one thing which elevates them above the miserable “straight leg” (non-jumping solder): the touch of insanity it takes to step out of an airplane at fifteen hundred feet.» —“A Collection of Airborne Cadence Chants” by George G. Carey Journal of American Folklore Jan.-Mar., 1965. (source: Double-Tongued Dictionary)
Further reading
The new book Bye Bye I Love You: The Story of Our First and Last Words (Bookshop|Amazon) by linguist Michael Erard is a deeply researched, often intensely personal exploration of the ways people communicate at both the beginning and end of life...
Leonor from Dallas, Texas, says that when she was a child, her Spanish-speaking mother and grandmother used to her after a bump or scrape with Sana, sana, colita de rana, Si no sanas hoy, sanarás mañana , literally, “Heal, heal, little frog’s tail...