The act of blowing your nose by a combination of covering one nostril with a finger and clearing the other with a powerful nasal blast of air, for use when a suitable snot receptacle isn't available. Popluar with farmers and footballers and useful in the right situation, but not really acceptable among polite company. Unless you're desperate of course.
The process of clearing ones nose without the assistance of tissues, hankies etc etc
More specifically, clearing ones nose by pushing one nostril down with the index finger and blowing out of opened nostril, subsequently shooting snot straight to the ground. The bushman's hanky must be executed with a fair level of pressure or the snot will end up smeared or 'looped' around the nostril (it may even lodge somewhere on the lower cheek or mouth region) rather than on the ground where it belongs.
Person 1: got any tissues bro? i gotta blow my nose
person 2: nah mate, just use the bushman's hanky...
person 1: wtf?
person 2: hold one of your nostrils down and blow that shit staright out.
person 1: pffft, thats fucked!
Person 2: Neck up ya cunt, thats the 'bushman's hanky'
A quick cleanup necessity for the strip club when a stripper/lap dancer bends over in your face and sharts, leaving you with fecal debris on your upper lip. Ewwwpsies.
Matt was in a strip club and after that voluptuous babe left him with a shizzler's lip, he pulled the shizzler's hanky out of his pocket and shazam, he looked swazzling; no worries the rest of the night.