South of the border refers to the genital area. More typically, the term is used to refer to a woman's genitals. The term refers to below, or south, of the waist.
More About South of the Border
The term south of the border is typically used to describe oral sex activities. When used as a verb, the phrase, to go south of the border means the giving of oral sex. The slang term is used most often to describe oral sex performed on a female, though can be used for male oral sex.
