Shenzi: Do you know what we do to kings who step out of their kingdom?Idiotic Partner Confession is a situation in which X is keeping something from Y, be it a something he's done, something he's planning, or just something he said earlier that he really doesn't want to tell Y. The problem is, Z is also aware of this secret, and just happens to be a complete idiot. So what does Z do? He starts talking about it right in front of Y, if not directly to him, of course! This will undoubtedly lead to X trying as discreetly as possible to get Z to shut up, with Z completely oblivious that he's saying anything remotely wrong. This will likely piss Y right off, and lead to all sorts of trouble for poor X. Y can be a villain, some sort of parental figure, or anyone else who X would have any reason not to be honest with. Z doesn't necessarily have to be an idiot to do this—just somewhat unaware of X's nervousness. Or it could very well be a case of Will Not Tell a Lie. Different from Right Behind Me, although the tropes might overlap. Compare Accidental Public Confession.
Simba: Phuh! You can't do anything to me!
Zazu: [nervous chuckle] Technically, they can. We are on their land...
Simba: But Zazu! You told me they were nothing but slobbery, mangy, stupid poachers!
Zazu: Ix-nay on the upid-stay...
Banzai: Who you callin' upid-stay??
— The Lion King