Typically the telephone companies would bill callers to chat lines and then remit 45% of the money collected to chat line operators.
When the Internet got relatively mature, sale of any sexual service not involving a minor could be made to anyone not a minor.
Phone sex is a conversation between two or more people on the phone where one or more of the individuals is describing the act of sex.
Phone sex takes imagination on both parties' part; virtual sex is difficult if the operator does not put the images in the head of the caller and the caller must be open to the pleasure as well.
The sexually explicit conversation takes place between two or more persons via telephone, especially when at least one of the participants masturbates or engages in sexual fantasy.
Phone sex conversation may take many forms, including: guided fantasy, sexual sounds, narrated and enacted suggestions; sexual anecdotes and confessions; candid expression of sexual fantasies, feelings, or love, and/or discussion of very personal and sensitive sexual topics.
This is the world portrayed in Spike Lee's movie about phone sex, Girl 6.