Or LO1 and LO2 about LO3, etc.? And how? How old were they? Did they understand?

LO is almost 3 and pretty verbal. I think he would parrot "baby in mommy' belly" to everyone without a ton of awareness of what that means lol. We haven't said anything about baby in front of him (still suuuuper early, so I'm really nervous).

Curious how and when others told their older LO(s) about the new baby?