Popularized by a Dave Chappelle impersonation of the 80's superfreak, Rick James. "Milk's gone bad" is in reference to the sight of a pair of less than favorable mammary glands.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".
I don't buy the schmegegge about Morty sleeping with Moira.
His version of the story was pure schmegegge.
The whole schmegegge was made up to get Liz a little bit of attention.