White trash refers to people of lower economic and social backgrounds.
White trash is an insulting term that is used to describe caucasian people who one considers low class. Since low class refers not only to social but also to financial standing, the term "white trash" can also be associated with the term "trailer trash" since residential trailers are often considered to be a dwelling for poor and uneducated people.
White trash is a term that originated in the southern part of the United States prior to the civil war - perhaps arond 1850. It referred to poor whites.
Some men and women find white trash to be sexually exciting. There are several issues involved here. Some people feel that an attraction to someone lower class shows them to be wild and untamed where others wish to feel they can sexually control those they perceive as lower class, and therefore inferior. Just as with thugs, white trash or trailer trash guys are generaly considered a little dangerous, or as with skateboarders, are considered to be slackers or unmotivated.