Mug Fuffin
Mug Fuffin - An insult used to describe someone who has acted in such a way which causes you to call them a Fuckin' Mug/Muffin. However in the anger/passion/frustration of your insult, the words have been jumbled.
"YOUR'E SUCH A MUG FUFFIN!" - "Oi that lad is a bit of a mug fuffin' int' he"