Don't make statements that imply forced sexual demands. Don't assume spending money on a date entitles you to sex. Don't allow others to attempt forced sex with another person. Communicate your limits clearly. Know what you are feeling and express yourself clearly.
Submissive behavior can encourage sexual aggression.
Passivity might be misinterpreted as permission. Be direct and firm with someone who is pressuring you sexually. If someone starts to offend you, respond promptly and firmly. Overly polite approaches might be misunderstood or ignored. Avoid excessive use of alcohol and drugs.