I usually say industrial sales.......it's vague enough that it doesn't matter and women usually aren't too interested in anything industrial. As a matter of fact, neither am I, but I usually don't have to go into a long story about it or anything. The couple times I was asked anything, I told them I sold machinery to factories........still friggin' vague as hell and they just shut up an moved on to the next topic.
Perhaps I should come up with something more exciting like stunt cock for midgets porn or something?