* A regional saying: Certain phrases are specific to particular geographic areas. If you heard it somewhere, it might be local slang.
* A specialized term: It could be used in a particular field or hobby, like gambling or sports.
* A misunderstanding: Perhaps there was a similar phrase you misheard or that was used in a way that made it seem like "coming up threes."
To help me understand better, please provide:
* The context in which you heard the phrase. Where did you hear it? What was being discussed?
* Any further information about the phrase. Was it used seriously or jokingly? Did anyone explain its meaning?
With more information, I might be able to figure out the origin of the phrase.