Carie's life could pretty well be summed up as being characterized by the adjectives lonely, sex-deprived, and horny.
Carie had the yearning to be licked in areas that males were completely unaware even existed. Rose was the kind of person who wanted to go out and have a good time, whereas Carie's goal was to have all of her pain sexuated away.
Dave is nothing more than a vivid dream that comes prepared when answering the cries of sex – bodies that are attention-starved and lonely and want to be acknowledged.