What does the idiom be between two mean?

The idiom "be between two" is not a common idiom in English. It's possible that you might be thinking of a similar idiom, or the phrase is being used in a more specific context.

Here are some possibilities:

* Be between a rock and a hard place: This means to be in a difficult situation with no easy choices.

* Be caught between two fires: This means to be in a situation where you are attacked or criticized from both sides.

* Be torn between two choices: This means to be unable to decide between two options.

If you can provide more context about where you heard the phrase "be between two," I might be able to give you a more accurate interpretation.