In Back Off! How To Confront and Stop Sexual Harassment and Harassers, Martha Langelan recommends taking these steps for confronting sexual harassment:
A person who has been assaulted  needs an empathetic listener who is nonjudgmental. Remain calm, and let the  victim do the talking. Encourage the victim to seek medical attention and  counseling.
Remember, it is the  victim’s choice how and who to tell about the assault. Be clear and upfront  about your ability to maintain confidentiality and reporting obligations. Listen without interrupting.
Do
Do Not
Bystanders are “individuals who observe violence or  witness the conditions that perpetuate violence. They are not directly involved  but have the choice to intervene, speak up, or do something about it.” They are  someone who is present and thus potentially in position to discourage, prevent,  or interrupt an incidence of sexual misconduct.” The South Carolina Technical  College System encourages all students, faculty, and staff to be engaged and  proactive bystanders. See some tips for bystander intervention below: 
   
Proactive  Bystander Strategies
   In  order to be a proactive bystander who helps prevent cases of sexual harassment  or sexual violence, you can… 
Reactive Bystander Strategies
   In  order to be a reactive bystander who positively intervenes in instances of  sexual harassment or sexual violence, you can… 
You are entitled to file a complaint of sexual harassment with your college’s Title IX Coordinator. The contact information for your college’s Title IX Coordinator is included on the college’s website and in its catalog. The Title IX Coordinator will walk you through the process of filing a report or formal complaint in accordance with the Student Code Procedures for Addressing Alleged Acts of Sexual Harassment Under Title IX (SBTCE Procedure 3-2-106.2) and will offer you supportive measures.