When you go to perform fellatio on someone and there is a particularly surprising amount of pubic hair.
Sarah met a guy on Friday night with no hair on his arms or legs, but when she went to give him a blowjob he had a Surprise Muffin.
by Yep_checks-out August 6, 2018
A particulary unpleasant fart that is completely unexpected by the party being surprised; usually in a setting that is not fart-friendly.
Sitting in church with my friend, I released a silent fart that packed a horrendous odor. I wispered to him that he had been muffin surprised. He was outraged and relocated to another pew.
by K.O.T.W. April 19, 2010