The formation principle is a basic principle telling the ways to form a euphemism in English and Chinese. Since, English is composed of alphabets, but Chinese are characters. So the formations between them are totally different.

There are six ways to form English euphemism: compounding, backformation, acronym, clipping, phonetic distortion and synonyms. Compounding method means to compound two or more words together becoming a euphemism which expresses something inconvenient to speak out. For example, “gezudna” is Backformation is the way to omit the imaginary affix to make a euphemism. This kind of words mostly are novel due to the fact that this way to build new words is not frequently used and that the words converted from backformation are not so many, for example, “bugle” is changed from “burglar”. Acronym equals to the combination of the first letter of every word. For example, “bowel movement” is replaced by “BM”. Clipping is the way to break off either end of the word, like “gentlemen’s room” turned into “gents lav”. Phonetic distortion mainly deals with the pronunciation similar to taboos, so the pronunciation of the word is varied with spelling unchanged. For instance, “god” is always read as “gosh” and “my god” is “my goodness”. Synonyms, the last way of forming English euphemism, refers to using better words to take the replacement of derogatory terms, such as “skinny” replaced by “slim”.

In Chinese, the ways to form euphemism are antonym, two part allegorical saying, pision, homophonic substitution. First, using antonyms is to take the opposite meanings of taboos, like “气死我” (piss me off) turned into “激生我” in Guangzhou. Here “死” is contrary to “生”. With the aid of Chinese two part allegorical sayings, the conversation could be vivid and these words make the blunt tone more circumbendibus. For example, when a staff is not very satisfied with his leader, he may say, “咱们经理也只不过是猪八戒的脊梁——悟（无）能之背（辈）”. Division refers to splitting Chinese characteristics into several characteristics to tell. This kind of way may result in humorous, satirical and euphemistic effects. For example, if you want to comment a person of his low level in some aspect, you may say that in Chinese, “你的水平自大多一点（derived from臭）”. As to homophonic substitution, this is a way to replace a vulgar word with the same sound but more graceful word. This is a Chinese characteristic kind of euphemism. For example, “扯淡” is just evolved from “扯蛋”.

2.2.2 The Principles of Distance and Correlation
Euphemism is an alternative to socially distasteful terms. Euphemism can be used to replace those tabooed words and widen the distance between a linguistic form and its referent. But a euphemism will lose its euphemistic function gradually after it has been used for many times and a long time, so a new euphemism needs to be generated. This is called distance principle. The euphemistic effect is usually in proportion to the distance, but being over-euphemistic may cause misunderstanding and breakdown in communication. For example, “ball” or an abstract term meaning something unknown can communicate a taboo body part like “penis”, and at the same time it functions as a euphemism in a specific context. 浅析跨文化交际中委婉语的应用(4):http://www.youerw.com/yingyu/lunwen_8489.html