A couple should have a clear understanding of each other's intentions. Women Know your limits. Believe in your right to set those limits - if you are not sure, stop and talk about it. If someone starts to offend you , tell them firmly and early. Polite approaches may be ignored.
Men often interpret passivity as permission.
Be direct and firm with someone who is sexually pressuring you. Be Aware that your Non Verbal Messages send a message, too. If you dress in a sexy way or flirt, some men may assume you want to have sex. It is very important to be aware and avoid misunderstanding. If you feel you are being pressured into unwanted sex, you probably are.