Mother's Milk is a resource from The Citadel. It first appeared in Mad Max: Fury Road.
Description[]
Mother's Milk is milk gathered from female humans via milkers. The women hooked-up to them, possibly Breeders, are seen with dolls in place of infants.
The War Rig was transporting some on board as revealed when they were stuck in the swamp, presumably for the two unborn children that Angharad and The Dag were carrying.
Max Rockatansky, after inquiring what it was, cleans the blood off his face with it.