Used precisely in legal contexts to avoid self-incrimination during a trial or similar proceedings.

Legal Specificity

The phrase is unique to the United States and derives its meaning from its specific constitution.

US Constitution

Invoking this right often carries a serious undertone and indicates the gravity of the legal situation.

Colloquially, it's a way to humorously avoid giving personal or potentially embarrassing information.

It's used informally to lighten the mood when not wanting to answer, not as a serious legal right.