A 'friend' of mine told me that he once said to an ex-girlfriend "fluff on your face", to which she replied "fluff on my face?" and he then proceeded to fart in her face. Now, at the time I took it on face value, but there are some issues here which plague me to this day.

1) How did he get his bum to her face without her noticing?
2) How widely spread is the term "fluff" meaning "fart"?
3) Why would anyone reply "fluff on my face?" and not "really, where?"

There are holes in this story, but he's not the sort of person to lie. This happened about a decade ago, yet to this day, I'm just not certain.