So, to help you reduce the risk of STI transmission and unwanted pregnancies, we've rounded up eight of the most common mistakes people make when using condoms. While a few of these tips are semen-specific, remember that it's also important to use condoms on any shared sex toys (they can't get you pregnant, but they can spread STIs). And if standard latex condoms don't work for you, just know that there are other sexual barrier options out there , like dental dams and female condoms.