You probably do not know you use the condom wrongly.

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.

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.

2. Add lube outside AND inside the condom.

Pro tip: Adding a drop of lube into the condom will make everything feel more awesome for the person wearing it.

3. But stay away from oils and lotions with latex condoms.

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.

4. Always check the expiration date.

Yes, condoms expire. Most last for a few years, but some condoms with added lubricants or spermicide have a shorter shelf life. So definitely check the label before you wrap it up.

5. Wait until the penis is erect before you put the condom on.

This way you can make sure it actually fits properly and stays in place when you're having sex.

6. Always leave some room at the tip of the condom to prevent spillage.

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.

7. Yes, there is a wrong way to put on a condom. Don't do that.

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.

8. The condom should roll down easily and reach the base of the penis.

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. There are SO MANY kinds of condoms, so don't settle for the first one you try.

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.

10. Make sure you're wearing the right size.

Again, it's 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. 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.

11. Make sure to use a new condom for every sex act.

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.

12. Most people stop using condoms way too soon.

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). 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.

13. Never ever double-bag it.

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.

14. If you're allergic to latex, you definitely still have options.

If you notice any itching or irritation after you have protected sex, you may have a latex allergy and not even know it. In this case, there are tons of alternative condoms you can try. You can try polyisoprene condoms like Okamoto and Sagami PU condoms.