Breast feeding

Last night I found Lucy on the couch with her baby up against her chest. I asked her if her baby was sleeping and she said, "No, I'm feeding her. She needs to poop." She then showed me how accurately she had her baby latched on. When she was finished and had burped her baby I heard this conversation,

Olivia: "Can you feed my baby for me?"
Lucy: "Ok."
Olivia: "Thanks. She's hungry."
Lucy: "No, I can't feed her. I have different milk. Your baby doesn't like my milk."
Olivia: "You have yucky milk?"
Lucy: "Yeah, I have yucky milk. Only my baby likes yucky milk."
Olivia: "Ok, I'll feed her. She doesn't like your yucky milk."