長布纏裹 Wrapped in Cloth
行者道：「想是調問哩。」不一時，捆綁停當，教把長頭布取十疋來。行者笑道：「八戒，這先生好意思，拿出布來與我們做中袖哩。減省些兒，做個一口中罷了。」那小仙將家機布搬將出來。大仙道：「把唐三藏、豬八戒、沙和尚都使布裹了。」眾仙一齊上前裹了。行者道：「想是调问哩。」不一时，捆绑停当，教把长头布取十疋来。行者笑道：「八戒，这先生好意思，拿出布来与我们做中袖哩。减省些儿，做个一口中罢了。」那小仙将家机布搬将出来。大仙道：「把唐三藏、猪八戒、沙和尚都使布裹了。」众仙一齐上前裹了。
逐句解 Line by line
The Pilgrim said, "This is likely for an interrogation."
調問, diào wèn, is summoning somebody for questioning, the official term; 調 here is diào, "to summon, transfer," not the tiáo that means "to adjust." Wukong assumes an interrogation is coming, and he is wrong.
In no time the binding was done, and he ordered ten bolts of long cloth to be fetched.
捆綁停當, the binding finished and in order, with 當 as dàng inside 停當. Then ten 疋, pǐ, bolts of 長頭布, long cloth — 長 as cháng, "long," not the zhǎng of "elder." Ten bolts is a great deal of cloth, and none of it is for clothes.
The Pilgrim laughed: "Bajie, this gentleman is very thoughtful—bringing out cloth to make us middle-sleeved gowns.
Wukong sees the cloth and decides it must be tailoring. 好意思, hǎo yì si, "how very thoughtful," said with the straightest of faces. 中袖, zhōng xiù, is a robe with sleeves of middling length — he is pretending to be measured for one.
"Cut it a bit shorter, and make me a single one-piece wrap and be done."
And he haggles over the material. 減省些兒, "economise a bit," with 省 as shěng, "to save," and the diminutive suffix 兒, ér; 一口中, one plain single garment, will do him. The joke is that a man about to be wrapped like a parcel is asking his captor not to waste good cloth.
That little immortal brought out loom-woven cloth.
家機布, jiā jī bù, is homespun — cloth off the household's own loom rather than bought in. The abbey wove it themselves, as they made their own lacquer; it is a self-sufficient establishment, and that domestic detail sits oddly next to what the cloth is for. 搬將出來 takes 將, jiāng.
The Great Immortal said, "Wrap up Tang Sanzang, Zhu Bajie, and Sha the Monk, all of them, in the cloth."
The order names all three by their full names, which gives it the ring of a sentence being read out. 三藏 takes 藏 as zàng; 都 is dōu, all of them.
The immortals came forward together and wrapped them up.
一齊上前, all forward together — and it is done.
Ten bolts of homespun cloth are brought out, and Wukong decides they are having clothes made. 這先生好意思 — how very thoughtful of the gentleman — and then he asks them not to use so much, since a plain single garment will do. It is gallows humour of a very pure kind: he is negotiating the cut of his own shroud.
The humour is doing real work. The chapter has arrived at torture, and the way it stays readable is that the victim will not take it seriously. Every escalation from here — the cloth, the lacquer, the cauldron of oil — is met with a joke, and the jokes get better as the situation gets worse.
Note the homespun, though. The cloth came off the abbey's own loom, as the lacquer will come from its own trees. This is a working household, doing something domestic with domestic materials, and the ordinariness of the equipment is more unpleasant than any instrument of torture would be.