A slut muffin is a term first coined in fall 2005 that describes a person who is appealing to the eye and is very charming. They can also be quite seductive.
A slut muffin is someone like Jim McMullen, Angelina Jolie, James Bond, etc. "As I heard him talk to those ladies at the party, there was no questioning his suave aura and the way his words escaped his mouth ever so smoothly. He was most certainly a slut muffin."