* It's a misspelling: It could be a misspelling of another phrase. Can you provide more context? What language is it supposed to be in?
* It's a slang term: It could be a slang term used within a specific community or group.
* It's a made-up phrase: It's possible someone created this phrase for a particular purpose, such as a joke or a song.
To help me understand what you're asking, please provide:
* The context: Where did you hear or see this phrase?
* The language: What language is this phrase supposed to be in?
* Any additional information: Do you know anything else about this phrase or its meaning?
Once you provide me with more information, I'll do my best to help you understand what "bi du di" means.