Guelleschiss is the extremely squishy and smelly result that you get upon having a dump after an afternoon full of alcohol and mexican food. It's something you can't hold but can't dump out neither.
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.