A term most commonly used by mouth breathers in the Bishop Auckland area of the United Kingdom. "Phuuuuuu, Yer What" is generally used during conversation as a reply to statement by another person in which "Phuuuuu, Yer What" essentially means "I agree"
Mouthbreather 1 -"These nappies for the bairns are a bit pricey like"
Mouthbreather 2 - "Phuuuuu, Yer What!"