Plague Ship by Andre Norton

Dane Thorson, Cargo-master-apprentice of the Solar Queen, Galactic Free Trader spacer, Terra registry, stood in the middle of the ship's cramped bather while Rip Shannon, assistant Astrogator and his senior in the Service of Trade by some four years, applied gobs of highly scented paste to the skin between Dane's rather prominent shoulder blades. The small cabin was thickly redolent with spicy odors and Rip sniffed appreciatively. "You're sure going to be about the best smelling Terran who ever set boot on Sargol's soil," his soft slur of speech ended in a rich chuckle. Dane snorted and tried to estimate progress over one shoulder. "The things we have to do for Trade!" his comment carried a hint of present embarrassment. "Get it well in-this stuff's supposed to hold for hours. It'd better. According to Van those Salariki can talk your ears right off your head and say nothing worth hearing. And we have to sit and listen until we get a straight answer out of them. Phew!"