裹漆留臉 Lacquered Head to Foot
行者笑道：「好，好，好，夾活兒就大殮了。」須臾，纏裹已畢。又教拿出漆來。眾仙即忙取了些自收自晒的生熟漆，把他三個渾身布裹漆了，渾身俱裹漆，上留著頭臉在外。八戒道：「先生，上頭倒不打緊，只是下面還留孔兒，我們好出恭。」行者笑道：「好，好，好，夹活儿就大殓了。」须臾，缠裹已毕。又教拿出漆来。众仙即忙取了些自收自晒的生熟漆，把他三个浑身布裹漆了，浑身俱裹漆，上留着头脸在外。八戒道：「先生，上头倒不打紧，只是下面还留孔儿，我们好出恭。」
逐句解 Line by line
The Pilgrim laughed: "Good, good, good—coffined alive, and all!"
The triple 好 again — last heard when he had just felled the tree. 夾活兒就大殮了, jiā huó'r jiù dà liàn le: 大殮 is the funeral rite of laying a body in its coffin, so the joke is "you're coffining me while I'm still alive," and 夾活兒 means exactly that, caught while still living. The suffix 兒 is ér.
In a moment the wrapping was finished.
須臾, xū yú, in a moment. 纏裹已畢, the swathing finished.
He then ordered lacquer to be brought.
And then the lacquer, which nobody has been expecting.
The immortals hastily fetched some of the raw and boiled lacquer they had gathered and dried themselves, coated the three of them all over the cloth-wrapping with it, coated them from head to foot, and left only their heads and faces exposed.
The lacquer is the abbey's own: 自收自晒, gathered from their own trees and dried in their own sun. Raw lacquer is the sap of the lacquer tree, and it sets to a hard, waterproof, immovable shell — the same stuff that makes lacquerware last a thousand years. 生熟漆, shēng shú qī, is raw and boiled lacquer, the two grades used together. It goes on over the cloth, head to foot, with only the faces left out. 上留著頭臉在外 takes 著 as zhe. 晒 is shài, to dry in the sun.
Bajie said, "Sir, up top it doesn't much matter, but do leave a hole down below so we can relieve ourselves."
And Bajie asks the practical question. 出恭, chū gōng, is the polite term for relieving oneself, and it has a wonderful history: the imperial examination halls hung a placard reading 出恭, "going out respectfully," which a candidate carried when he left his cell for the latrine, and the euphemism escaped into the language. It is roughly as if English said "excuse me" for the act itself. 孔兒 takes the diminutive suffix 兒, ér; 上頭倒不打緊 takes 倒 as dào, "as for that."
Cloth, then lacquer. Three of the four are wrapped and then sealed head to foot in the abbey's own home-gathered lacquer, with only their faces left out — which is to say they are set inside a shell that will harden and cannot be cut off. It is the single most frightening thing that happens in the chapter.
And the pilgrims joke through the whole of it. Wukong compares the wrapping to being coffined alive; Bajie, in the middle of being sealed into a case, asks whether they might leave a hole at the bottom. The novel has a firm rule about this: the more helpless the disciples become, the funnier they get, and the reader is never allowed to be frightened for long.
Bajie's word for it is worth the detour. 出恭, "going out respectfully," was the wording on the placard an examination candidate carried when leaving his cell for the latrine during the imperial exams, and it drifted from the placard into the language as the polite term for the act itself. A pig sealed in lacquer is using bureaucratic vocabulary.