What is the origin of the idiom "spit it out" and when to use it?

The origin of the idiom "spit it out" is not precisely documented, but it is used to encourage someone to communicate more directly and openly. It likely developed organically in the course of everyday language use over time. The phrase conveys the idea of prompting someone to share their thoughts or information without hesitation or delay, and it has become a standard way of encouraging clear and direct communication.