As long as you're up, get me a Grant's.

This line is best understood as a piece of mid-to-late 20th-century American barroom or household banter rather than a traceable literary quotation. “Grant’s” most plausibly refers to Grant’s Scotch whisky (William Grant & Sons), a widely distributed blended Scotch brand. The phrasing “As long as you’re up…” is a common conversational setup used when someone is already standing or heading to the kitchen/bar, turning a casual request into a small joke about convenience and mild entitlement. It circulates as an anonymous quip, often implying a relaxed, slightly tipsy social setting—friends watching TV, a party, or a nightcap—without a stable attribution or single originating moment.

The humor comes from its casual opportunism: the speaker leverages the other person’s movement (“you’re up”) to justify asking for a drink. It conveys familiarity and a low-stakes social dynamic—someone comfortable enough to make a mildly presumptuous request. Naming a specific brand (“a Grant’s”) adds character: it suggests habitual taste, a working-class or everyday-drinker register, and a preference stated with mock decisiveness. As a quotation, it functions less as wisdom than as a snapshot of social ritual—how small favors, alcohol, and joking entitlement can signal camaraderie (or, depending on tone, mild irritation).