Level 1 - Lesson 16 ~ Repulse Monkey and Diagonal Flying with Martial Applications
"Step Back to Repulse the Monkey" implies the image of a monkey grabbing your extended arm and attempting to use it as a vehicle for reaching your centre. The movement is also sometimes called "Step Back to Repulse LIKE a Monkey", suggesting that we, like a monkey are retreating while simultaneously threatening the opponent.
(A monkey puts on a brave face and uses distraction and trickery to conceal its true cowardice.)
"Diagonal Flying" traditionally follows "Repulse Monkey" for strategic reasons. Both movements are useful for manipulating the vector of an opponent's attack, causing him or her to engage away from our centre. "Repulse Monkey" creates chaos in the opponent's footwork, and "Diagonal Flying" exploits this chaos to send the opponent on a conveniently (for us) oblique tangent.