Do Not Understand?
You have a moralistic obligation and professional obligation to report anybody that you deem as acting in an inapproriate way, this is regardless if you know the person, work for them or yourself feel pressurised into keeping this information quiet. A number of people have posted threads here which mention 'sense of humour' ,'keep your hat on' that is such an awful and wholely unacceptable attitude and not one becoming of anyhbody that is in a position of authority (ie Officer). Just think if something happened and you hadn't spoken up....what would that say about you?
You can call an equal opportunities/harrassment phone number, speak to OC PSF,OC PMS, Chf Clk, speak to your Flt Cdr or Sqn Cdr, Padre, SSAFA Social Worker, anything you tell people should be taken serious and you should not be treated any differently for highlighting a potential problem. My only other piece of advise is try to get the individual herself to make the complaint, or maybe you could both go together?