Hair-trigger

His id is a minefield of hair-trigger rage, and his ego is snowflake-fragile.

I have always held, too, that pistol practice should be distinctly an open-air pastime; and when Holmes, in one of his queer humours, would sit in an arm-chair with his hair-trigger and a hundred Boxer cartridges, and proceed to adorn the opposite wall with a patriotic V. R. done in bullet-pocks, I felt strongly that neither the atmosphere nor the appearance of our room was improved by it.

[…]the hunter brings the sight of his rifle to bear; lightly and delicately his finger presses upon the hair-trigger.

Is your laugh hung on a hair-trigger?—that is, is it critical, or can you get it off easy?

"Gus," the latter began, "am I right in assuming that you possess a reasonable amount of influence with that hair-trigger partner of yours, Live Wire Luiz?"

[I]n the 575 days since [Oscar] Pistorius shot dead his girlfriend Reeva Steenkamp, there has been an unseemly scramble to construct revisionist histories, to identify evidence beneath that placid exterior of a pugnacious, hair-trigger personality.