As a professional wordsmith, I am very interested in learning new expressions. Lately I've been exposed by my sons to several new terms regarding flatulence, and cannot stop myself from sharing them here:
1, Buttercup: When you pass gas into your hand, clench your fist and then open it in someone's face.
2, Cropdusting: When you pass gas near the face of a sleeping person.
3, Arabian gas mask: Even I refrain from defining this in public. It is disgusting.
These and much more can be found at the Urban Dictionary.