Debi (的逼) is Beijing slang for talking bullshit, or something like 'yak yak yak' or 'yada yada yada'.

The below is translated from Massage Milk, the excellent blog of Wang Xiaofeng, an editor at Life Week magazine (三联生活周刊).

De bi is a vulgar word often heard in Beijing.

Beijingers have a habit of blindly adoring reproductive organs: they often add the word bi [slang for vagina] to express their meaning more clearly or for greater effect.

For example, a motorized scooter for disabled people is often called can mo [short for disabled person's motorbike], but for Beijingers, it's called a que bi le, which you might translate as 'fun for lame cunts'.

It is a little insulting to disabled people, but it is really representative of Beijing humor.

It is not worth promoting this kind of humor, but from all these words that are made using bi, we can tell what Beijingers are thinking about all the time.

The 'de' in de bi is pronounced in the first tone, and longer than the usual 的. It's usually used in the string "debi debi de".

Other Beijing slang words made up with the word bi are:

Shi er bi 事儿逼
While de bi means being too talkative, shi'r bi means having too much shi'r: too many issues, problems, random stuff going on, headaches, always something to break your balls about.

Er bi 二逼
Pretentious, stupid, foolish in an annoying way

Sha bi 傻逼
Stupid person, idiot

Niu bi 牛逼
Cow vagina, which means either really cool, or being pompous, swaggering or boastful

You can add bi on to the end of many adjectives using the following grammatical principle:

"Adjective" + bi = Very (特) "adjective" person (的人).

Adding a little more bi to our lives, a commentor on Massage Milk contributed the following:

A lot of people don't say de bi, but de'r bi (得儿逼) with a lot of stress on the 'er'. That de'r means the male reproductive organ, the counterpart of the bi. It means talking so much that the bullshit never ends, just like the male and female reproductive organs are constantly twined together.