* A misspelling or slang term: It might be a corrupted version of a real word or phrase, specific to a certain region or group.
* A made-up term: Someone might have invented it for a specific context, like a fictional story or a joke.
To understand the meaning, you'll need more information:
* Context: Where did you hear or see this term?
* Source: Was it in a book, movie, song, or online?
* Language: What language is it supposed to be?
Please provide more details so I can help you figure out what "bong lalang" means.