Work or function at a peak level of performance.

Work as expected, or at 100%
Teller: The lady tried to rob the bank using her fingers as a gun
Police: She doesn't seem to be firing on all cylinders
by smoking_acez January 8, 2018
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To sneeze, poop, and urinate all at once on the toilet.
Dave: Man Paul, you in the bathroom for a long time.
Paul: Yeah, I was Firing on all cylinders.
by Seems Like Science March 31, 2015
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