If you are in immediate danger of being raped, here are some things that you can do.
Make a loud noise - Carry a whistle or scream "police" to attract attention
Run - Only run if there is somewhere safe to run to. If there is no where to go you may aggravate the assailant further by running
Stall - Speak calmly and rationally. Try not to plead, cry or show that you're scared, this may be the reaction that he's going for.
Urinate or vomit - Do anything you can to repulse the assailant. Tell him that you have a STD or AIDS.
Fight - Women who resist attacks and act quickly are less likely to be raped, than those who are passive. The optimum time to react is in the first 20 seconds when the body releases chemicals in the blood that help to put up a fight. Be cautious if he has a weapon.
Keep alert - Even though it will be difficult, try to pay attention to as many details as possible, so that you can identify your assailant.
Get help - Call 9-1-1 as soon as possible. Police are becoming more willing to help victims of rape. You are not obligated to press charges or go to court.
Collect evidence - Do not bathe, shower, or douche. If you change clothes, put the clothes you were raped in into a bag and seal it.
Tell someone - Call the police, rape crisis counselor, telephone operator, friend. It is very important that someone knows and that it is not kept a secret.