滿身解數 Up Three Down Four Left Five
好獃子，駕起風頭，也到半空，丟開鈀，上三下四，左五右六，前七後八，滿身解數，只聽得呼呼風響。正使到熱鬧處，沙僧對長老道：「師父，也等老沙去操演操演。」好呆子，驾起风头，也到半空，丢开钯，上三下四，左五右六，前七后八，满身解数，只听得呼呼风响。正使到热闹处，沙僧对长老道：「师父，也等老沙去操演操演。」
逐句解 Line by line
Fine Idiot! He rode up on a gust, reached mid-air himself, set his rake going — three up, four down, five left, six right, seven forward, eight back, a whole body of technique — and all that could be heard was the wind roaring.
The counting is the joke and the pleasure both. 上三下四，左五右六，前七後八 runs the numbers three to eight through six directions in strict pairs, so the line scans like a drill being called out. It is nonsense as description and perfect as rhythm — you cannot see what he is doing and you can hear it exactly. 解數 again, with the first character read xiè. Pilgrim got two named techniques; Bajie gets arithmetic.
Just as it was getting lively, Sha Monk said to the elder, "Master, let old Sha go and drill a little too."
Sha Monk asks permission, which neither of his brothers did. 操演 is to drill or exercise — a plainer, more military word than the 耍, playing, that Pilgrim used and the 耍耍 Bajie used. He doubles it, 操演操演, which softens it into something modest: just a little drill.
Three brothers, three ways of asking to go up. Pilgrim announces the yard is too small, Bajie shouts that he is going, and Sha Monk asks his master's leave.
Their vocabularies are as different as their manners. The eldest plays, the second plays about, and the third drills. Nobody in the novel says any of this out loud and the word choices say all of it.
The counted directions are the sort of thing that looks like filler until you read it aloud. It is a fairground barker's line, and it belongs to Bajie in a way the named techniques never would.