An expression of annoyance or disgust from the South West of England, and can be applied to just about anything from physical objects and people to ideas and opinions. It originated quite literally from something getting into the nasal passages and causing pain, irritation and aggravation. From there its use expanded to cover just about anything that causes annoyance, exasperation or discomfort. It is now used widely throughout the UK.
When you're goin down on a girl and you use your tongue in her cum box and your nose in her clit to maximize the experience.
I was gonna go sturgeon fishing the other day and boy howdy did my nose get a wiff of that fish when I proceeded to go to town with the Bergman nose technique.