Hehehe, well, your right, I should ask the instructor...but you know how it is sometimes, you're the new guy and you don't want to sound too stupid not even being able to throw a proper punch. So, when the instructor says to snap your punches I'm like "OK, I'll try that thank you." Mean while, I'm thinking what did I just say OK to?
I did ask him and basically, you're all right. I'm extending my arm out for too long and it turns into more of a push than a punch, so I need to "snap" the punch than retract it back into a defensive position.
I think part of it is instict to punch that way, and part of it that I used to take Kung Fu, and a lot of that it pattern based, so for a pattern, you usually left your arm extended longer for visual effect or something? It's sctually quite difficult to throw a proper punch, who knew. Skipping rope is also something I'm TERRIBLE at, I used to be able to skip, if I had two people holding the ends, I'd jump in, say a few rhymes and then jump out...but that's not really the type of skipping were doing in class, though it would be funny if it was.