The one-two is a technique means always having a rod rigged up with a soft plastic jerkbait that you can cast to a fish that has missed your other lure.
I used to make the mistake of casting the same lure back to the fish. On the odd occasion it would work and I would catch the fish but more often than not, the second time around the lure would be refused.
If a fish strikes a lure short, it normally means that it has simply missed the lure or, more importantly, that something about the lure turned it off at the last second...