For many, especially in the Southern US, it means the person referenced is an ignoramus . That is, if the person had their shoes shined. they could easily be fooled by the shine man who could just as well put shit on their shoes as shoe polish
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.
Looking or experiencing something nice after witnessing something horrid like a disgusting gif or a disturbing video. Typically used as eye bleach are nice images of whatever makes the disturbed person happy.