Don’t worry, we got you.

Knowing what to do when your girlfriend is on her period can feel like a shot in the dark. It’s often confusing to women, too. Our vaginas are bleeding and our emotions are on a roller coaster. We feel like laughing one minute and crying the next. Most likely, your girlfriend doesn’t blame you for not knowing what to do. Still, getting an insider’s look at what happens during her period, how you can help, and what you should most definitely not do will help you help her. Read on!

Understand the changes her period causes.

One of the best ways you can be supportive of your girlfriend during her period is to take some time to learn about what is happening in her body. It can seem mysterious at first, but with a little understanding of the complex process of menstruation, you’ll become more aware of why she feels and acts the way she does. This will give you the tools you need to communicate with your other half in a way that makes her feel loved and empowered. And trust us when we say that this will go a long way.

The four phases of the menstrual cycle.

The first thing we are going to cover is what happens in each phase of the menstrual cycle. This is a process that repeats each and every month, so being aware of what’s happening (and when) can give you invaluable clues on how to be a great support system for your girlfriend.

The Menstrual Phase. The menstrual phase is the time when she has her period. It can last anywhere from 1 to 7 days, depending on her body. Some women have even longer periods, though it’s not nearly as common. What happens during this phase is that her uterus begins to shed its lining—this is where her period blood comes from. Though it may seem like she’s bleeding a lot, most women only release between 2 and 3 tablespoons of blood each period. Having cramps is a normal, albeit unpleasant, symptom during this phase. They are caused by her uterus contracting in order to shed the lining.

The Follicular Phase. The follicular phase starts at the same time that her period starts, but lasts up to 13 days. During this time, your girlfriend’s pituitary glands secrete a hormone that signals to the ovaries that her egg cells need to grow. One of these egg cells will mature and, during this time, the uterus will begin to develop a new lining.

The Ovulation Phase. During ovulation, your girlfriend’s pituitary gland releases a hormone that causes the ovary to release the mature egg cell into her fallopian tubes. This phases only lasts a couple of days, at most.

The Luteal Phase. The egg hangs out in her fallopian tube during the luteal phase—but only for about 24 hours. It’s waiting to see if your sperm is going to fertilize it. If you aren’t having protected sex and she does get pregnant, the egg will begin the process of implantation. In other words, you’re going to be a dad. However, if the egg isn’t fertilized, it will be absorbed into her uterine lining and she’ll get her period. The entire process starts all over again.

It can be a bit confusing but these are just the basics. Don’t stress about trying to remember all of these things. It’s more of a foundation for what we’re going to cover next—hormones.

Her hormones are wreaking havoc.

There are lots of stereotypes about how women act during their period. Some people say their girlfriends get “crazy.” (Pro Tip: Never, ever say this to your girlfriend. Seriously, not cool.) Some women admit to getting mad at the sound of their partner’s breathing. Still, others say that they want to eat everything in sight and hide in their bed until the bleeding and concurrent pain and irritability stop. All of these emotions may feel totally overwhelming to you. You want to help but aren’t sure how to approach her.

Let’s get one thing straight first: It’s not her fault. Her hormones are constantly fluctuating throughout each month and can lead to some pretty intense feelings. Just like we covered what happens physically during each phase of menstruation, we’re going to cover the hormonal changes and how they may affect her emotional well-being.

Here’s what each phase really means:

The Menstrual Phase. Every woman is different, especially during the menstrual phase. For some, the start of her period may bring relief from the cramps and cravings. Others may feel more tired than normal and experience painful cramps. It’s a really individual thing.

The Follicular Phase. During the follicular phase, a hormone called estradiol begins to rise. This hormone is known to lessen feelings of stress caused by cortisol and adrenaline. Her estrogen is also on the rise, which can make her feel cool, calm, and collected. Your girlfriend is likely to feel the best during this time of the month.

The Ovulation Phase. There’s a very scientific explanation for what happens during the ovulation phase, but we’ll keep it short and sweet: That estradiol that started rising during her follicular phase makes her insulin more effective. In turn, this signals to the body that it needs to release more testosterone. The result? She’s likely to have a higher libido than any other time of the month. Lucky you! Just make sure to take extra precautions during this phase if a baby isn’t in your near future plans—ovulation is the time when women are the most fertile.

The Luteal Phase. Here’s where the trouble really begins. Her body is creating more progesterone, which can make her feel moody. Add this to the extra cortisol that tends to be present during this time and her stress levels may be higher than usual. Studies have shown that, during the luteal phase, women tend to crave comfort foods and are more likely to indulge.

An important thing to remember is that period symptoms aren’t always related to hormonal changes. In fact, many of them are related to a woman’s lifestyle. Drinking alcohol, eating a lot of sugar, and not working out can all contribute to feeling less-than-amazing during her period. Don’t criticize her if she’s doing these things, though. Instead, ask if she wants to take a walk, offer tea instead of wine, or whip her up a healthy dinner that will help ease her period pains.

All women menstruate differently.

The bottom line is that no two women are the same. While your ex may have been totally chill during her period, your current girlfriend may be really irritable. Being aware of this and avoiding comparisons is key. Don’t bring up how your sister or your ex acted. Let your love know that while you can’t even imagine how it feels to have hormones constantly changing, you are there for her and want to support her in any way you can.

Ask her what she needs.

This brings us to the ever-important topic of how exactly you can help ease her period pains and become Partner of the Year. The truth is that there’s no one way to do this. What works for some women may be the exact opposite of what your lady needs. Your best bet is to simply ask her, “How can I help?” Make sure she knows that you mean it and be open to her answers.

Here are some ideas to get your creativity flowing:

• Be patient! Don’t blame her irritability on her period, but try to understand where she’s coming from.
• Bring her the food she craves. Whether it’s ice cream she’s after or she’s one of the rare women who crave a green juice, just go and get it. She’ll appreciate it forever (or at least until next month).
• Be attentive. It’s simple, really. Just pay attention to her. Ask about her day. Let her vent to you. A little TLC can go a long way.
• Give her a massage. A good one. And don’t complain about it.
• Give her space. Your girl may just want to Netflix and chill by herself. Be OK with that. She’ll come back to you when she’s ready.

The main point here is to not assume what she needs. Instead, ask. Find out what will make her feel better. Then do it. Remember, the worst thing you can do is ask and then not deliver.

Be an advocate for period-positivity.

Men around the world have been known to throw out, “Are you on your period?” at the most inopportune moment. Word to the wise: Just don’t. Rarely, if ever, has this question or any like it been met with a pleasant response. Actually, it’s pretty degrading. Instead of assigning her behavior to her period, be an advocate for period-positivity by understanding and demonstrating that her feelings are valid regardless of whether she’s on her period or not.

Another way to be period-positive is to go and get her tampons if she needs them—without feeling embarrassed about. Seriously, no one thinks they are for you. (p.s. Target carries Cora. Don’t get her the tampons full of chemicals. Her vagina will not thank you.)

Lastly, on this note, do your best not to make her feel embarrassed. The world is full of period-shaming and she doesn’t need it from you. Ask her if she wants to talk about what she’s going through, but if she doesn’t, back off and let her know that you’re there in case she changes her mind.

Oh, and don’t forget period sex. This seems to be a divisive topic, but let us lay down a few truths for you. Period sex is not gross—because periods are not gross. Period sex is messy, yes, but so is using lube. This is just a natural version of what you might use already. Period sex can also help ease her cramps and boost her mood. Being open to having sex when she’s on her period is a great way to be period-positive.

If you want even more brownie points…