muff muffin
A term derived from the latin word, "muffcake", but translated to english. 
Short for your-stupid-and-you-think-you-know
-everything-but-
you-just-suck-at-life-and-need-to-die.

Can also be used in place of eff.(see examples)

"Andrew is the biggest muff muffin of life...fosh!"
or
"What the muff muffin are you doing?"