If you do a good job as a gigolo, clients will often want you to stay back for longer than the appointment time. And if you do a great job, she will often beg and plead with you to stay a little longer.
It may feel flattering that a client wants more of you and you may be tempted to stay on, without charging extra. I have made the mistake.
Don’t do it.
The longer you stay with her without charging her extra, the less she will value you and your time, and less the chances of her hiring you again (even if she does hire you again, she will presume that ‘extra’ time is included for the same cost).