i've heard of this, called a corkscrew, designed to open a cut by twisting. as monkey said, also helps snap. (a bit I suppose). trouble is, it's conducive to bringing your elbow up early, telegraphing your punch. you'll also tend to hit with the back of the hand. ie, pure garbage.

whoever taught you this should stick to teaching kids self esteem through his McKarate. the word "course" is all we need to hear to know what way the wind is blowing.

it's a f'in joke. run for the hills. or a legit boxing gym where they know what they're talking about, unlike this asshole who's got a black belt despite never being so much as punched in the face.