It's often used in situations like:
* When something unexpected happens: "Carajay, I can't believe we won!"
* When someone does something impressive: "Carajay, that was an amazing goal!"
* When you're simply surprised or amazed: "Carajay, what a view!"
It can also be used to express frustration or annoyance, similar to "damn" or "shoot".
Important Note: "Carajay" is considered informal and colloquial. It's not appropriate for formal situations.