Contrary to its recent misuse as a euphemism for audacity or courage, to have "brass balls" actually means to drive a hard bargain and to refuse to sell for less than what you ask for.
The term dates back to the days when pawn shop brokers would traditionally hang three brass balls outside their shop doors to indicate their services.
A pair of metallic spheres, each approximately 2 inches in diameter, connected by a string or chain and meant to represent the male testes. Used as a motivational tool by Alec Baldwin in the 1992 film version of David Mamet'sGlengarry Glen Ross.
'Brass balls' are what Santa'selves need, when they complete their work for Christmas. Reference comes from 2005 Saturday Night Live skit, featuring Alec Baldwin.
Alec Baldwin waved those brass balls in front of Santa'selves - was that a call to glory, or just showing off?