How do you "sit" on a punch? What is punch "leverage"? How do you transfer weight?

https://www.youtube.com/watch?v=Uv2leT3cBOU

30 seconds in.

 

It depends on which angle your throwing the punch, for exmple after you throw a straight right you will be on the inside with more weight (not all your wieght) on your front foot. When your throw the left hook you simultaniously shift more wieght to your rear foot while turning your hips and shoulders into the punch. But remember to maintain a good stance for good balance.

So your on the right track with wieght transfer idea. But the wieght transfer comes from turning your hips and shoulders into the punch.