The word rotten crotch can be traced back to a relatively remote dialect vocabulary-Ganzhou dialect. The original meaning of "rotten crotch" is that the hem of trousers is broken, and the word "rotten" in Ganzhou dialect means "broken" The word "rotten crotch" has become a colloquial slang because of its wide spread and use on the Internet. It is mostly used for online chatting and entertainment, and many people even use the screen name "rotten crotch".
Although the word rotten crotch can play a certain entertainment effect in some cases, it is recommended that you use it with caution in formal occasions or when communicating with strangers, because the word rotten crotch is often regarded as a vulgar and uncivilized expression, which is easy to cause unnecessary embarrassment, so it is more appropriate to use a general expression in daily life.