LUNCHY BACK NINE
Fat, Thick or Full Butt, Backside or Arsze, most often female. I originally heard this saying from a young male work colleague ('Milky') (Police Officer) when he was describing the physical appearance of a female.
When referring to a female's butt. "She has a Lunchy Back Nine" means it is a bit full and thick like the thickness of grass on the back nine holes of a golf course.