Green’s Dictionary of Slang

stock n.4

(N.Z. gay) a male sex worker’s supply of lubricant and condoms .

[NZ]W. Ings ‘Trolling the Beat to Working the Soob’ in Int’l Jrnl Lexicog. 23:1 73: Terms like on-site visuals (personal appearance), stock (lubricant and condoms), and ugly mug (a dangerous or potentially violent client), became part of the [male sex worker] vernacular .