A Riley riddle from my neighbour:

Ma prefex es a salfush beest,
Ma suffex es oor ‘Noo’.
Ma enfex es joos tha’, yous sees,
Ma all, oor fustive doo.

Um, I'm not sure if you caught all that, so allow me to provide an alternative rendering:

Their prefix is a greedy swine,
Their suffix their negation.
Their infix I’d consider ‘mine’,
Their whole their celebration!

What is the answer to my neighbour's riddle, and where do we both live?

(Please explain both riddles and the title!)