Who is B from The Philosophy of Andy Warhol and what is their importance?

B is anyone in Andy Warhol's life who helps Andy kill time by talking. It is interesting to note that B normally does most of the talking and Andy merely listens, whether on the phone or in a face-to-face contact. B can be anyone of any sex or any age as shown throughout the book. Sometimes B is a male traveling companion and sometimes B is an older female friend who phones Andy to talk for hours on end.