The only way to ensure that you are 100% safe from HIV transmission is to abstain from sex. Outside of abstaining from sex, you can decrease your risk for HIV transmission by using a new condom each time you have sexual intercourse, to include oral sex. For oral sex on a woman, the use of a dental dam is recommended in order to decrease the risk of HIV transmission.
There is more than one type of barrier available for oral, anal and vaginal sex, the first being the male condom. The male condom should be used according to the manufacturer's instructions with a water-based lubricant for anal and vaginal sex. Also available are flavored male condoms that can effectively be used for oral sex on a male. These are not recommended for vaginal penetration, as they can cause yeast infections given that they are often coated in sugar. The second most common type of protection is the female condom. This should also be used according to the manufacturer's instructions with lubricant for vaginal sex. A couple should not use a male condom and a female condom at the same time as this will cause one or both of them to rip or tear. Lastly, dental dams are recommended for oral sex on a woman and also come in assorted flavors.