Sexual Health: Safe Sex Mistakes to Avoid

You'd know if you had one, right? Not so fast. Some sexually transmitted infections (STIs) have mild symptoms or none at all. If you're sexually active, talk to your doctor about testing or visit a health clinic. They'll take some of your blood to test or have you pee in a cup.

Condoms help protect you from STIs and pregnancy, but only if you use them the right way. Only put a condom on an erect, or hard, penis. Pinch any air out of the end and roll it all the way down. When you're finished having sex, hold the base of the condom and pull out.

Don't forget to check the expiration date. If a condom is dry, sticky, or stiff when you take it out, toss it and use a fresh one.

The only surefire way to avoid them is to not have sex -- oral, anal, or vaginal -- or swap bodily fluids. Most forms of birth control, like pills or intrauterine devices (IUDs), won't protect you from STIs. Barrier forms of protection, such as condoms and dental dams, lower your chances of infection and pregnancy.

Your chances of getting pregnant from anal sex are low, but it's not impossible. That's because semen can move from your anal area to the vagina. STIs are your main concern, though. Rectal tissue is thin and can tear easily, letting infection in. Use a condom every time you have anal sex. And use plenty of lube. Condoms are more likely to break during anal sex because there's less natural lubrication.

Pregnancy is more common around the time your ovary releases an egg (ovulation). That's around the middle of your cycle. You're most fertile during these 5-7 days, including the day of ovulation and 3-5 days before. If you have a shorter menstrual cycle and have sex toward the end of your period, you could get pregnant 4-5 days later.

Some people think you can't get pregnant the first time you have sex. But this just isn't true. Whenever sperm is in or near the vagina or vulva (the vaginal opening), there's a chance of pregnancy. The only way to avoid getting pregnant is to not have sex. But if you do, be sure to use condoms or some other form of birth control.

Also called the withdrawal method, the goal is to take your penis out of the vagina before you climax, or ejaculate. But it's risky for a few reasons. It takes self-control to pull out in time. And sperm can still get into the vagina through fluid that comes from the penis before you ejaculate. There's also no protection against STIs.

You or your partner can have no symptoms and still have an STI. This means you can infect each other. Always use a condom during sex and get tested regularly for STIs.

Douching, or cleaning your vagina with water or a special solution, doesn't protect you from pregnancy or an STI. In fact, it can spread an infection to other parts of the reproductive system like your uterus and fallopian tubes. Your vagina cleans itself.