champagne tap

Etymology
An indication of atraumaticity in the proceduralist's technique, warranting the reward of a bottle of champagne from their superior, the colour of which also matches that of the cerebrospinal fluid sample.

Noun

 * 1)  A bloodless sample of cerebrospinal fluid from a lumbar puncture (colloquially, a spinal tap).
 * 2) * year unknown, Sandeep Jauhar, The Intern:Doctor's Initiation, Penguin Books India (ISBN 9780143063827), page 39:
 * When the needle finally perforated the sac around the spinal column, clear fluid bubbled back through the hub. The resident congratulated me on a “champagne tap”, free of blood. We sent the fluid off to the laboratory.