The highlights:

  • A menstrual disc sits in the vaginal fornix (a.k.a. the widest part of your vagina and the base of your cervix) whereas a menstrual cup is placed in the vaginal canal
  • Both menstrual discs and menstrual cups collect your period blood, rather than absorbing it 
  • Cups and discs involve different insertion and removal steps
  • Menstrual discs are held in place by gravity (and tucked behind your pubic bone); menstrual cups are kept in place with suction

The full read:

Calling a menstrual disc and a menstrual cup the same product would be like equating eyeglasses to contact lenses. Sure, both of them do the same thing (correct your vision), but they’re totally different products that are used in different ways. 

Both menstrual cups and discs are period products designed to collect menstrual fluid, but their designs and ways of working in the body are quite different. Read on to learn the key differences between a menstrual disc and a menstrual cup – including how they are used, the materials they’re made from, positioning in your body, and what activities you can do with each period product.

Menstrual disc vs. menstrual cup placement

A menstrual disc sits in the vaginal fornix, which is at the base of your cervix. This area is the widest part of your vaginal canal, which is why the disc looks wider than a cup. Menstrual cups, on the other hand, sit lower in the narrower, lower portion of your vagina – the vaginal canal. 

If you’re familiar with tampons, both tampons and menstrual cups sit in approximately the same position in the vagina. With a menstrual cup, you’ll have a bit more control over exactly where (or how far up) the product is placed than you would with an applicator tampon. This is because you use your fingers to manually place the menstrual cup in the right position for your body. 

Flex Disc inserted in the vaginal fornix (left); Flex Cup inserted in the vaginal canal (right)

How each product works: Different mechanisms

A menstrual disc stays in place because your anatomy (including the muscular vaginal walls and the pubic bone) works together to keep it “propped up” within your vaginal fornix. The fornix is the widest part of your vagina and is located at the end of the vaginal canal, “surrounding” your cervix. 

With the pubic bone serving as sort of a shelf and the vaginal muscles somewhat contracted, your menstrual disc stays comfortably tucked down and back – and gravity helps with this, too. When it’s time to remove your menstrual disc, you just use a finger to hook the rim of the disc, “untucking” it from behind the pubic bone, and carefully pull it out. 

In contrast, a menstrual cup uses suction to stay in place (plus a little help from the vaginal muscles). When it “pops” open in the vaginal canal, the edges of the cup create a seal against the vaginal walls, preventing leaks and keeping the cup in place. Therefore, when you want to remove a menstrual cup, you have to break the suction seal by pinching the base of the cup. 

With the Flex Cup™, breaking the seal is as easy as pulling down on the patented pull tab – we designed our cup to work similarly to a tampon for greater ease of use and a less messy removal. 

Menstrual cup insertion vs. menstrual disc insertion 

In order to insert a menstrual disc, you pinch it in half (so that it’s about the same size as a tampon), insert it into the vagina with two clean fingers, and then use a single finger to push it down and back into the vaginal fornix. Once it’s as far back as possible, you use that same finger to position the front-facing side of the rim up and back, tucking it behind your pubic bone.

Pinch Flex Disc to insert (left); fold Flex Cup to insert (right)

Inserting a menstrual cup requires folding (rather than pinching) as the first step. There are several folding methods you can try, including the punch down-fold, the C-fold, and the 7-fold. 

Once you’ve mastered your fold, insert the folded cup into your vaginal canal with clean fingers. As soon as it’s in a comfortable position far enough up your vaginal canal, use a single finger to ensure the cup has popped open properly. Some users like to rotate 360 degrees to help the disc create a tight seal with your vaginal walls; you may also run your finger around the rim to ensure it’s completely unfolded. 

Watch the difference in cup versus disc insertion in these two videos:

How to Insert Flex Disc (YouTube)
How to Insert Flex Cup (YouTube)

Menstrual discs are disposable; menstrual cups are reusable

If you want to create as little waste as possible during your period, a menstrual cup is your best choice – they are reusable and hold up for years (so long as you take good care of them). 

Menstrual cups must be emptied and washed before reinsertion; they should also be boiled every month at the end of your period to completely disinfect them. For daily washes, we recommend using a mild soap that won’t damage the cup’s material. Our favorite? Flex Foaming Cup Wash, designed specifically for cleansing silicone menstrual cups.

Flex Disc is disposable (left); Flex Cup is reusable (right)

Menstrual discs, on the other hand, are disposable. Since you can wear most menstrual discs for longer than you would a tampon or pad (Flex Discs can be worn safely for up to 12 hours), they still create less waste than traditional period products. Some users find them more convenient when traveling or in public restrooms, because they do not need to be washed or boiled after each use – you simply dispose of them.  

Sex on your period: Can you have sex with a menstrual disc?

A menstrual disc doesn’t block the vaginal canal, so it is possible to have mess-free, penetrative period sex while continuing to wear it. It’s unlikely that either you or your partner will feel the disc, thanks to its positioning in the vaginal fornix, which is wider than the vaginal canal (and located at the very “back” of your vagina, surrounding your cervix). 

The same is not true for a menstrual cup: Because the cup sits inside the vaginal canal, it blocks anything else from entering. Therefore, you’ll need to remove your menstrual cup before having penetrative sex. 

Flex Disc can be used during sex (left); Flex Cup cannot (right)

Cups & discs: Different materials

Most menstrual discs are made from body-safe polymers – including Flex Disc, which is made from a medical-grade polymer. Medical-grade polymers are FDA-regulated materials used in many types of medical devices, including surgical tools. 

Menstrual cups are usually made from medical-grade silicone, although some brands use different materials, such as rubber or latex. Flex Cup™, specifically, is made in the USA out of 100% medical grade silicone. Flex products are FDA registered, hypoallergenic, BPA- and phthalate-free, and made without natural rubber latex.

Have questions about Flex Cup or Flex Disc? Need help deciding which product is best for you? Our Flexperts are always available to chat: Just send us a message or email us at