Most horny studs don't need a zip code from an attractive lady to get him to "bare da goods" to her... usually all she hasta do is drop her OWN drawers, and he's only too quick to reciprocate.
if your first girlfriend or boyfriend is in another post code or zip code then you can date another person in your same post/zip code
If your First girlfriend is in Brisbane and your in Sydney then you are able to go out with someone in your same post/zip Code or city without feeling bad. Known as the Post/Zip Code Rule