揣在他懷裡 Tucked Into His Sleeping Breast
他卻回身，徑到八戒站處，只見那獃子嘴拄著牆根，卻是睡著了一般。行者更不驚他，將榜文摺了，輕輕揣在他懷裡，拽轉步，先往會同館去了不題。他却回身，径到八戒站处，只见那呆子嘴拄着墙根，却是睡着了一般。行者更不惊他，将榜文折了，轻轻揣在他怀里，拽转步，先往会同馆去了不题。
逐句解 Line by line
Then he turned back and went straight to where Eight Rules was standing, and there was the Idiot with his snout propped against the foot of the wall, for all the world as though he had fallen asleep.
Two instances of 著 in one sentence, read differently. 拄著 takes the weak zhe of an action in progress; 睡著 takes zháo, which marks a result achieved — sleep fallen into rather than sleep going on. It is the first appearance of that reading in the chapter, which until now has used only the weak zhe and the zhuó of setting somebody to a task.
Pilgrim did not disturb him at all, but folded the proclamation, tucked it gently into his breast, swung round on his heel and went off ahead to the Hall of Common Assembly — of which we shall say no more.
拽 is zhuài, to pull — 拽轉步 is to haul the feet round — not the zhuāi of hurling something, which is the default. And 揣 is the same chuāi that stowed a snout inside a shirt in the street scene. What is stowed now is evidence.
更不驚他 — he did not disturb him at all — does a great deal of quiet work. Pilgrim takes care not to wake him, and the gentleness is real and entirely in the service of the frame-up.
The planting is described just as flatly as the theft: fold, tuck, turn, go. No gloating, no aside to the reader, no statement of intent. The narrator has already told us Pilgrim was playing with him in the market and does not think it necessary to say so twice.
不題 closes the thread for the second time in this chapter, and on both occasions it shuts the door on the person just abandoned — first a king at his table, now a pig at a wall with stolen state property in his shirt.