Alice Mongkongllite / BuzzFeed So condoms are a fantastic way to prevent STIs and babies. But you probably already knew that. Lemontreeimages / Getty Images / Via thinkstockphotos.com They're your best defense against STIs and HIV, and they're up to 98% effective at preventing pregnancy when used correctly. But actually, using condoms ~correctly~ is a little more complicated than just grabbing the nearest rubber and calling it a day. So whether you're using condoms as birth control or a barrier against STIs that can be transmitted via oral/anal/vaginal sex, make sure to keep the following facts in mind: 1. The condom needs to be worn the WHOLE time. avert.org In order for condoms to work their magic, they need to be worn for the entire duration of the sex — even if you're also using another method of birth control. In one recent study, only 59% of people who used condoms with another birth control actually kept the rubber on the whole time. (The rest of them put it on after some genital contact or took it off before they finished.) This is a big problem, because any skin-to-skin genital contact can lead to STIs. So put it on right at the beginning, and keep it on until you're finished. 2. Add lube outside AND inside the condom. Tap to play or pause GIF Tap to play or pause GIF safeinthecity.org / Via youtube.com Pro tip: Adding a drop of lube into the condom will make everything feel more awesome for the person wearing it. Some condoms already come lubed up, but adding your preferred kind can't hurt, sex therapist Ian Kerner, Ph.D., founder of GoodInBed.com, tells BuzzFeed Life. Plus, extra lubricant on both sides of the condom may also help prevent tearing. 3. But stay away from oils and lotions with latex condoms. Eatcute / Getty Images / Via thinkstockphotos.com Stuff like coconut oil, lotions, massage oils, and petroleum jelly can all break down latex, so stick to silicone-based or water-based lubes instead, sex researcher Debby Herbenick, Ph.D., author of Because It Feels Good, tells BuzzFeed Life. 4. Always check the expiration date. Tap to play or pause GIF Tap to play or pause GIF NBC / Via popsugar.com Yes, condoms expire. Most last for a few years, but some condoms with added lubricants or spermicide have a shorter shelf life, says Herbenick. So definitely check the label before you wrap it up. 5. Wait until the penis is erect before you put the condom on. Tap to play or pause GIF Tap to play or pause GIF forums.somethingawful.com This way you can make sure it actually fits properly and stays in place when you're having sex, says Kerner. 6. Always leave some room at the tip of the condom to prevent spillage. Tap to play or pause GIF Tap to play or pause GIF safeinthecity.org / Via youtube.com The tip of the condom is called the reservoir, which holds the cum after you ejaculate in it. Make sure to squeeze the tip when you put the condom on, so that there's room for the ejaculate — otherwise, it might spill out the sides, says Kerner. 7. Yes, there is a wrong way to put on a condom. Don't do that. Tap to play or pause GIF Tap to play or pause GIF Planned Parenthood / Via youtube.com If you accidentally put the condom on upside-down (where the rim is facing down instead of up), it probably won't unroll all the way. Just take it off and start fresh with a new condom, since that one could have some pre-ejaculate on it, says Herbenick. 8. The condom should roll down easily and reach the base of the penis. Tap to play or pause GIF Tap to play or pause GIF Planned Parenthood / Via youtube.com To put a condom on properly, carefully unwrap it by tearing the corner of the wrapper (not by cutting or ripping it, since you might break it). Then place the condom on the penis and gently pinch the tip of the rubber so you leave a little room in the reservoir. Roll it all the way down to the base of the penis. Make sure it fits snug — but not too tight — so it won't slip or break when you're having sex. 9. Don't wait too long after you finish to take the condom off. Tap to play or pause GIF Tap to play or pause GIF safeinthecity.org / Via youtube.com Most men lose their erection pretty quickly after they ejaculate, says Kerner. So you'll want to take the condom off before you go soft, since that could mean a lot more room in your condom and more opportunities for semen to spill out or the condom to slip off. When taking off the condom, hold the rim as you pull it off to prevent any spillage. Bonus points for tying the end in a knot before you toss it in the trash. 10. There are SO MANY kinds of condoms, so don't settle for the first one you try. Tap to play or pause GIF Tap to play or pause GIF Warner Bros. / Via nmonicaa.tumblr.com Condoms come in all shapes, sizes, colors, and textures. There's super-thin, ribbed, smaller-fit, extra-long, flavored, lubricated, glow-in-the-dark, and even vegan condoms. Those free ones from your health clinic are great and super-effective too, but if they don't feel amazing to you, try other options. Don't just assume that all rubbers feel the same. 11. Make sure you're wearing the right size. Tap to play or pause GIF Tap to play or pause GIF Universal Pictures / Via taniaburrito.tumblr.com Again, it's really really important to try out different condoms to find one that's best for you. If the condom doesn't roll all the way down to the base of the penis or if it just seems too tight, it probably is. Condoms actually very rarely break, so if it's happened to you a few times, you probably need a larger size or more lube, says Herbenick. If the condom seems too roomy or it slips or slides when you're having sex, look for a smaller size. And keep in mind that you might be one size in one brand and another size in another brand — just like jeans, sex educator Elle Chase tells BuzzFeed Life. 12. You probably don't need spermicide. View this photo on Instagram instagram.com Some condoms contain a spermicide called nonoxynol-9 for added pregnancy protection, but it's probably not necessary. The World Health Organization (WHO) states that there is "no evidence that nonoxynol-9-lubricated condoms provided any more protection against pregnancy or sexually transmitted infections than condoms lubricated with silicone." Earlier reports also found that spermicide may be irritating if you use it a lot, so you can just skip it if you're using condoms. 13. Putting on a condom should be another part of foreplay, not an awkward inconvenience that kills the mood — and the boner. View this photo on Instagram instagram.com You can make it part of the sex act without being cheesy, says Chase. Keep touching and kissing as you put it on (or put it on your partner), turn it into a handjob as you add the lube, and definitely keep condoms close so you don't have to stop everything to find one. 14. Yep, you should be using condoms for oral sex, too. Tap to play or pause GIF Tap to play or pause GIF NBC / Via reactiongifs.com Research shows that people only use condoms during oral sex about 10 percent of the time, says Herbenick. So, yeah, realistically we know you're probably not going to adhere to this one. But just know that ideally the safest sex practice would be to use a condom or dental dam during oral sex, and that's really your best defense against STIs and HIV. Flavored condoms or flavored lubes can make this a little more appetizing, says Chase, but you might have to experiment to find one you really like. Remember: Just because most people aren't using protection for oral sex, that doesn't mean you should forgo it or feel silly for requiring it. It's your body, your decision, and your risk. The ~safe~ thing to do is use a condom. 15. Make sure to use a new condom for every sex act. View this photo on Instagram instagram.com So you know you should be using a condom for oral, anal, and vaginal sex. But if you're doing more than one of these, make sure to take off the condom and use a new one for each new, um, hole. This helps reduce your risk of STIs and other infections, says Kerner. 16. Most people stop using condoms way too soon. MTV / Via butnotquite.tumblr.com Of course no one expects you to use condoms with your partner forever, but the decision to stop using a barrier method of protection should only happen if you've talked about it, you've both been tested for STIs, you're mutually monogamous, and you have another way of preventing pregnancy (if you're worried about that). Unfortunately, most couples just stop using condoms randomly and way too early on, says Herbenick. If you do this before you've talked about it and before you've both been tested, you're putting yourself at risk for STIs. 17. Female condoms are just about as effective as male condoms. fc2femalecondom.com / Via youtube.com They're 95% effective at preventing pregnancy when used correctly, and they're FDA-approved to prevent STIs and HIV. The only problem is, most people have no idea what the hell they are. Here's a video that explains exactly how to use them. 18. Never ever ever double-bag it. Tap to play or pause GIF Tap to play or pause GIF FOX / Via gifbay.com Using two condoms will not give you double protection, and neither will using a male condom with a female condom. All this will do is make them more likely to tear, which would actually put you at increased risk of infection and pregnancy. Don't worry, one is enough. If your condom does break or slip off and you're worried about pregnancy, you can get the morning-after pill. 19. If you're allergic to latex, you definitely still have options. Pederk / Getty Images / Via thinkstockphotos.com If you notice any itching or irritation after you have protected sex, you may have a latex allergy and not even know it, says Chase. In this case, there are tons of alternative condoms you can try. You can try polyisoprene condoms like Skyn or Durex Avanti Bare RealFeel or polyurethane condoms like Trojan Supra BareSkin. There are a bunch of options, so just look for a box that says "non-latex," suggests Herbenick. You can also opt for lambskin condoms, but those do not protect against STIs (only pregnancy).