Who is Tanya from Women and what is their importance?

Tanya is twenty-three, petite, and weighs only ninety pounds. Henry describes her as being 'red hot' and very sexual. Tanya likes to drink and has read all of Henry Chinaski's books. They meet after she sends him a letter with a nude photograph of herself. She later visits Henry in Los Angeles, where she spends about a week at his apartment drinking and having sex.