NOUN: A yellowish/greenish brown substance with the consistency of a chocolate milkshake which occurs when motor oil and engine coolant/antifreeze mix together. One may discover baby shit on one's dipstick after blowing a head gasket or wearing a hole in one's front cover. Termed because it resembles actually newborn baby fecal matter. May also be called a milkshake.
At first when I discovered the baby shit on my dipstick, I thought I blew my head gasket, but it turns out my timing chain bracket broke, over time allowing the timing chain to wear a hole in the front cover of my s13. I was angry and sad. I cried.