撲撲搧搧 Flapping with Their Caps
他都摘了頭巾，脫了衣服，又沒把扇子，只將僧帽撲撲搧搧。你挨著我，我挨著你，直到有二更時分，卻都睡著。他都摘了头巾，脱了衣服，又没把扇子，只将僧帽扑扑扇扇。你挨着我，我挨着你，直到有二更时分，却都睡着。
逐句解 Line by line
They all took the headcloths off and stripped their clothes, and having no fan between them, flapped away with their monks' caps.
撲撲搧搧 doubles both halves of beat-and-fan, and doubling a verb this way makes it continuous and slightly futile — they are not fanning themselves so much as flapping on and on. 將 is jiāng, the one that puts the object before the verb.
You pressed against me and I against you, right up to about the second watch — and then they all fell asleep.
Three of the same character in one line and two different readings between them. 挨著 twice is zhe, pressed and staying pressed; 睡著 at the end is zháo, falling asleep, something that happens to you. And 更 is gēng, the night watch: the second of them runs to about eleven.
The detail that gives it away is the monks' caps. They have kept them — the one thing that would convict them on sight is in the box with them, being used as a fan.
It is also the most physically uncomfortable passage in a chapter that has been about comfort throughout: grades of service, singing girls, warmed wine, a good airy room with the windows open. All of it has ended in four men sweating against each other in the dark.