"I have eaten so many Muffnuts i think i'm going to puke. Mark my words one day i will find a way to fuck thisdelicious animal of tasty & give birth to its delicious jam filled offspring."
A cornucopia of muffin related items in combination with a doughnut. I.E. a Blueberry Muffnut!
or
One who enjoys the experience of muff diving, to the extreme as to where they could be considered a "nut"
or
One who enjoys the experience of frolicking in womans vagina head first!