The outcome of actions made by someone who has no shame or awareness of the action in question. "Mad woman's shit" comes from mental-health institutions. When a woman is crazy enough, she will shit anywhere. Then she will throw, spread and smear her shit around her environment. She has no shame or awareness of her actions.
She was driving was so erraticly, her car was all over the road like a mad woman's shit.
The boy threw a dozen eggs at the wall and the eggs were everywhere like a mad woman's shit.
Michael's work was so messy, it was all over the joint like a mad woman's shit.