Don't jump and punch, it wouldn't add more energy in your punch but only a push so it would look like you punch harder.
This kind of stuff is more intuitive and natural than it is technical. The kind of thing a guy finds works for him with experience, and he understands when and how its works for him.. or just something that you do because you see an opening or that happens out of instinct and rhythm…. but not necessarily something you would “train” so much.. Some would say things like this are “bad” or “wrong” and generally speaking, I agree and I’d generally disagree with attempting to teach things like this to someone. On the other hand, boxing history is filled with ATG fighters who did stuff “wrong” and made it very effective for them… Ali, Roy Jones, Manny Pacquiao.. to name a few.. So nothings off the table, but at the same time there are best practices, and techniques like these ain’t included in that.
Ricky Hatton was the prime example of leaping in with a corkscrew piston like jab. It would snap the head back like Berets so it would leave them open for a following in close variety of punches. Someone mentioned timing, yes while the opponent is not expecting it . And experience, Hatton knew how to use it to his advantage. A straight up brawler move methinks he did it visibly in probably the Kosta tszyu fight, Paulie Malignaggi, but maybe not in the Cotto fight because he got his butt handed to him. So leap in with the jab, snap the head back, then hit them with a punch while they're stunned, classic stuff!