Using a condom (or any form of barrier birth control) during period sex is must for STI prevention. Not only does it make for easier after-sex clean up, which is especially important if your partner is squeamish about blood, but it lessens your chance of contracting bacteria.

"Blood in general is a medium for bacteria," Dr. Alyssa Dweck, OB/GYN, assistant clinical professor at Mount Sinai School of Medicine, and author of V is for Vagina, tells Bustle. "If blood in the vagina or uterus is exposed to some bacteria during unprotected sex, there are more places for bacteria to grow."

Dr. Sherry Ross, OB/GYN and author of She-ology, agrees. “It’s true that women can be more at risk for sexually transmitted infections during a period,” she says. “The period blood does create a healthy petri dish for organisms to grow and thrive. Wearing a condom is definitely important in preventing STIs during your period.”

While period sex won't have you looking like Carrie in Stephen King's classic 1976 movie Carrie after you and your partner finish, it's important to choose your positions wisely. For example, the spooning position or missionary sex are going to be your best bet from a gravitational perspective. “Positions that have gravity working against you, like being on top, may create more of a crime scene than being on the bottom,” Ross tells Bustle. “Being on the bottom with your partner holding your legs up at a 180-degree angle may also be helpful.”

Think about it: If you're on top, there's likely to be a bit more blood than if you were on the bottom — it's just basic science. So if you want to limit how much blood you have involved in your period sex, seriously think about what sex positions you want to avoid and which ones you want to try. “It’s more [about] trial and error and not using your favorite white bed sheets while you experiment,” Ross says.

As Dweck tells Bustle, some of her patients have opted for shower sex when one partner is menstruating as a means of saving their sheets because… well, blood stains. But while that definitely seems like a great idea, it can be unexpectedly challenging.

For starters, shower sex can be dangerous because it's so slippery. Then, if you toss in some menstrual blood — some of which is bound to at least trickle down your leg — things get even more slippery. Before you know it, you're both slip-sliding in the shower, and one of you, if not both of you, ends up falling.

You might be better off staying on a flat surface and trying another less difficult alternative. “Some women will use a tampon right before having vaginal penetration,” Ross says. “Others lay a towel down on top of the bed sheets, while others use a menstrual cup [before sex] to collect the blood so there is no evidence of blood dirtying the sheets.”

Lots of things come up when people talk about period sex, but one topic that doesn't come up enough is the fact that you can get pregnant when you’re bleeding.

Technically, you cannot get pregnant during your actual period, but it’s not quite as simple as you might think. "If you're really having your period, then you ovulated two weeks ago, you did not get pregnant, and you're shedding uterine lining," Dweck tells Bustle. "If that is really the case, then you can't get pregnant because the window of fertility is gone."

But the problem is that so many people with vaginas have irregular periods, so if you don't know exactly when you're menstruating and ovulating, the risk is there. Ross explains that people with shorter menstrual cycles may be at risk of getting pregnant during the final days of their period. “If you have 21 days between day one of your last period to day one of your next period, you probably ovulate on day 10 of your cycle,” she says. “If your period lasts seven days and you have sex on day seven, it’s possible to become pregnant on day 10 since sperm lives for three to five days.” Plus, blood doesn’t always mean you are menstruating — in some cases, it may be a sign of spotting between periods.

It’s better to assume that pregnancy is still possible from penis-in-vagina penetration and to plan accordingly. “Always play it safe and use a reliable birth control method, even on your period,” Ross suggests.

Of course, period sex is different for everyone. For some people, it’s NBD, but for others, it requires trust and an extreme level of comfort. Exposure to bodily fluid like blood can create real intimacy, and some even believe that period sex is soul binding with the other person. While there’s no official science to back this up (your brain releases the same chemicals during sex regardless of where you are in your cycle), it’s understandable if you don’t want to have period sex with just anyone.

But don’t let this deter you if you want to try it out! “It’s definitely a personal preference,” Ross says. And you should never have to feel like anything is wrong or bad when you are menstruating — it’s just your body doing its thing.

If the whole period-sex soul-binding thing sounds like a bunch of hippie jargon to you, there’s still a very enticing reason you may want to give it a shot. When we discuss period sex, we usually address how it feels and the logistics of keeping the blood as minimal as possible. But this skips one major selling point: Period sex (whether alone or with a partner) can relieve menstrual cramps and make your period less miserable.

“Orgasms during period sex can help relieve the pain associated with period cramping,” Ross explains. It’s just one of the weird things that happen in your brain after sex: During orgasm, your body releases chemicals like dopamine and oxytocin that literally help your muscles relax. This, in turn, can alleviate menstrual cramping and discomfort.

With every contraction that comes when you orgasm, the uterine lining and blood are expelled. And while this doesn’t impact the amount that you bleed, it might shorten the length of time you are bleeding or spotting once your actual period is over. “Some believe having period sex makes your periods shorter since the uterus pushes out the blood faster,” Ross says. So, if your period seems shorter after having period sex, this could be one reason why.

In addition to the many benefits of period sex, it also feels really good. Why? Well, for a lot of people, they're hornier than usual when they have their period. Also, because you are menstruating, there's no need for lube, so things are really slippery and fun. “Some women love having sex on their period since the blood acts as a perfect lubricant,” Ross says.

Even if you don't climax, sex on your period still feels great. “There is more blood flow to the uterus, cervix, and vagina during that time of the month, and some enjoy the fullness during sexual stimulation,” Ross notes. “Some women feel as though their orgasms are stronger during their period.”

When you’re on your period, sometimes life can just seem a little — or a lot — extra rough. It’s an annoyance, it can be painful, it’s messy — it's a stressful week, to say the least. “For some women, their period can be stressful if it comes with cramps or heavy bleeding,” Phillips adds, which is why a little action can be the perfect antidote. “Having sex for some (in and outside of menses) can be a physical stress relief and help not only with cramps but release neurotransmitters that are also relaxing in nature,” she continues.

Sex will help relax you even without climaxing, but bonus points if you do. “Orgasm during your period can release stress and help with painful periods just as much as a workout,” Phillips tells Bustle. And thank goodness for that, because having your period at that gym can be a real pain.