A piquant piece of writing, published some time ago in The Economist, with examples from other cultures than English, too.
One feature of Chinese euphemisms comes from the tonal nature of the language. Yan is slang for cigarettes; jiu means alcohol. But, with different tones, the two syllables together can also mean “to research”. So a corrupt official being asked to do something might suggest, “Let’s research (yanjiu) this issue together”, by which he would probably mean, “Give me some cigarettes and some alcohol and I’ll make it happen.”