To get on a bus before buying a ticket.

先上車，後補票。

[PinYin] Xian1 Shang4 Che1 Hou4 Bu3 Piao4

To have a child before getting married.

[Talk Show] Foreigners' marriages in Taiwan

A clip from Taiwanese talk show "Kang Xi Lai le".
Guests include: Canadian, Brazilian, Pole, Japanese, Congolese... etc.

You may wonder: Is the host guy trying to flirt with that female guest?
No worry! Kevin Tsai is a well-known openly gay in Taiwanese Show-biz.

To take off one's pants before farting

脫褲子放屁

[PinYin] Tuo1 Ku4 Zi3 Fang4 Pi4

Do something unnecessary.

When your fart, do you need to take off your pants? Of course not. We use this slang to describe someone when he does an unnecessary act. Vulgar, perhaps, but vivid and funny.

[Example]
明明就有線上請假系統可以看，老闆還是規定每個人請假要交假條，真是脫褲子放屁。
Despite the existence of online submission system, the boss still requires everyone to give him an application paper for leave. That is so unnecessary.

[Joke]
A foreign friend of mine once felt puzzled about this slang and asked why one need to take off his pants before farting. We asked him to guess the meaning. Then he said it must me "Be careful", because you never knew if you would meet a shit pretending to be a fart! :D Well... it makes sense, right?

To pretend to be fat by beating one's face

打腫臉充胖子

PinYin: Da3 Zhong3 Lian3 Chong1 Pang4 Zi

Try to satisfy one's vanity when one cannot really afford to do so.

Literally, this slang means to beat one’s face until it’s swollen in an effort to look imposing; metaphorically, it means to do something beyond one’s means.

Example:
自己都快不能吃飯了還要借錢給朋友，何必打腫臉充胖子？
Why are you lending out money to your friends when you can’t even afford to feed yourself?

Dead pig is not afraid of hot water.

死豬不怕開水燙

[PinYin] Si3 Zhu1 Bu2 Pa4 Kai1 Shui3 Tang4

A dead mouse feels no cold. (Homologous English Idiom)

Immersing pork into hot water is an essential step before cooking it. If the pig is still alive, it may struggle and scream loudly. If it is dead, it is not able to sense the hot water.

You can use this slang to describe someone who appears to be unscrupulous, regardless of anything. It is a little rude though, since in Chinese culture pig usually refers to a negative meaning.

Example:
他的醜聞又多了一樁，但是本人一副死豬不怕開水燙的樣子。
There comes another scandal of him, but he himself seems not to mind at all.

Of the Thirty-Six Stratagems, fleeing is best.

三十六計，走為上策
[PinYin] San1 Shi2 Liu4 Ji4, Zou3 Wei2 Shang4 Ce4

The best strategy is to run.

This idiom originated in Ancient Chinese tactician Sunzi's book "Art of War" used to illustrate a series of stratagems used in politics, war, as well as in civil interaction, often through unorthodox or deceptive means. The last one of them is "Fleeing is best", teaching us that when situation goes too dangerous or out of control, it won't be a bad choice to retreat.

You may use this idiom to rationalize one's decision to escape or not to do something.

(The comma is not necessary.)

Example:
三十六計走為上策，他決定不要留在這裡。
Of the Thirty-Six Stratagems, fleeing is best. He decided not to stay here.

Open one eye, close one eye.

睜隻眼閉隻眼
[Pin Yin] Zheng1 Zhi1 Yan3 Bi4 Zhi1 Yan3

To pretend to know nothing about something unethical or improper.

Imagine this face: when you open one eye and close when eye, it's like you are appeasing something you have known. You may use this slang when you beg someone to forgive: "Please open one eye and close one eye. (請您睜隻眼閉隻眼吧！)"

[Example]
她對丈夫的外遇睜隻眼閉隻眼。
She pretend not to know about her husband's illegal love affair.