Well, the same thing that anybody should do who is accused of any crime, falsely or accurately. However, if someone is falsely accused of a sex offense, it raises the stakes, and so the most important thing to do is to be quiet, do not give a statement, and immediately contact a lawyer. In this area of the law, more often than not, the person is not arrested and has a chance to consult with a lawyer before the charge is made. And so the important thing is: find a good lawyer immediately.