Can refer to any attractive female. But usually refers to girls who are making a conscious effort to look attractive - whether they really are attractive or not - and thus are, presumably, currently interested in
sex ("
wet", "horny", "turned-on", "easy"). These women are disposable like a "
wet nap" - the pre-moistened, disposable towelettes given out at some restaurants.
At the
mall yesterday, we got followed by a
couple of wet naps but they were way too
young for us so we ditched them.