A person with kids who is oblivious to everything besides the fact that they've procreated.
Mom: Oh I know I'm living in squalor but I just love kids! And I'm going to get pregnant for the 5th time regardless of my situation! It's a miracle!
Normal person: Wow that bitch is a real breeder brain.
When a mother can't help but throw her being a mother into a conversation, regardless of relevance. Usually done by mommy martyrs to gain sympathy or attention of some kind.
Stacey: I want to buy a green car.
Anne: My kid popped green before!
Stacey: Wow, mommy jacked much?