Pump
Although its literal Chinese meaning is to draw water, it’s used as a slang with several meanings. First, it means to take advantage of or profit from other people's success. Second, it means criticising or ridiculing others.
O-shaped mouth
“O-shaped mouth” refers to being speechless and tongue-tied because of something unexpected or surprising. It is usually used to describe someone whose mouth is wide open into an O-shape to show their surprise.
Eating peanuts
"Eating peanuts" is equivalent to getting the popcorn in English. Recently in Hong Kong, it means someone is watching a conflict develop between other people, sitting back back as if one were at a movies.
Crab stick
“Crabstick” is processed seafood made of starch and finely pulverised white fish, shaped and cured to resemble the leg meat of the crab. It imitates to be a crab when in fact it is not.
Therefore, Hong Kong people use it as a metaphor to satirise someone who is hypocritical and is good at pretending.
Hong Kong local slangs