The most common way to fold a menstrual cup is the C-fold: pinch the rim flat, then fold the cup in half lengthwise so the rim forms a C or U shape. But that’s just one of several folds, and the best one for you depends on your anatomy, your cup’s firmness, and how easily it pops open once inside. Here’s how each fold works and how to get a reliable seal every time.
The C-Fold
This is the fold most people try first because it’s the simplest. Hold the cup with the rim facing up, pinch it flat between your fingers, then fold it in half lengthwise so the two edges of the rim meet. The rim now looks like the letter C. It’s easy to hold and easy to release.
The tradeoff is that the C-fold creates the widest insertion point of any fold. If insertion feels uncomfortable, one of the narrower folds below will likely work better.
The Punch-Down Fold
This fold creates a much smaller tip than the C-fold, making it a popular choice for beginners. Hold the cup upright in one hand. Place your thumb on one spot along the rim and press it straight down toward the base of the cup, pushing that section of the rim inside the cup itself. You’ll end up with a narrow, pointed tip that looks like a small V. Grip the base firmly to keep it from springing open before you’re ready.
The punch-down fold inserts easily, but it can be slightly harder to pop open once inside because the rim is tucked inward. If you have trouble getting it to unfold, the next section on troubleshooting will help.
The 7-Fold
Start by pinching the cup flat, just like the C-fold. Then take the top right corner of the rim and fold it diagonally down toward the opposite edge of the base, forming a shape that looks like the number 7. Hold firmly near the base to keep it compact. This gives you a narrower insertion point than the C-fold while still leaving part of the rim exposed, which helps the cup spring open more reliably than a punch-down.
The Labia Fold
If you’ve tried the standard folds and insertion still feels too wide, the labia fold creates the smallest overall diameter of any fold, both at the tip and through the body. Pull one side of the rim down into the cup’s interior to form a small pocket, then fold the left and right sides inward around each other and roll the whole thing into a long, thin shape. It takes real dexterity and works best with softer, thinner cups. Firmer cups resist the fold and are hard to keep compressed. This fold is worth the effort if size during insertion is your main barrier.
How to Insert Any Fold
Whichever fold you choose, the insertion technique stays the same. Find a comfortable position: sitting on the toilet, squatting, or standing with one foot up on the edge of the bathtub. With one hand, gently separate the labia. With the other, guide the folded cup rim-first into the vaginal canal. Aim toward your tailbone, not straight up. The vaginal canal angles back, so pointing the cup horizontally keeps it on the right path.
Once the entire cup is inside, release your grip and let it unfold. You’ll often feel a slight pop or shift as the rim expands.
Getting the Cup to Pop Open
A cup that stays partially folded inside is the single most common cause of leaks. The rim needs to expand fully and sit flush against the vaginal walls to create a seal. When positioned correctly, the space between the cup and your cervix is sealed off from outside air, and the cup stays in place through gentle pressure against the vaginal walls, not suction alone.
To check whether the cup has opened, slide a clean finger along the outside edge of the rim. If you feel any dents, creases, or flat spots, it hasn’t fully expanded. A few fixes work well:
- Rotate the base. Grip the bottom of the cup and twist it slightly in either direction. Even a small rotation can break the tension holding the fold in place.
- Press the vaginal wall. Insert a finger beside the cup and gently press the vaginal wall outward. This creates a small air gap that lets the cup expand.
- Use your pelvic floor. Contract and release your pelvic floor muscles (the same muscles you’d use to stop the flow of urine) a few times. The subtle pressure shift is often enough to nudge the cup open.
Once the cup feels round and smooth all the way around, give the stem a gentle tug. If you feel resistance, the seal is set.
Cervix Height Changes the Placement
Your cervix height determines how deep the cup should sit. You can check yours by inserting a clean finger into your vaginal canal and feeling for the cervix, which feels like a firm, rounded nub (similar to the tip of your nose). If you reach it at the first knuckle or less, roughly 44mm or shorter, you have a low cervix. If you can insert your finger most of the way before touching it, around 55mm or more, you have a high cervix.
With a low cervix, the cup sits closer to the vaginal opening, and you may need to trim the stem so it doesn’t protrude. With an average or high cervix, there’s more room in the canal, and a longer cup body works well. In either case, the cup should sit below the cervix, not around it, held in place by the vaginal walls.
If One Fold Doesn’t Work, Try Another
Different folds suit different cups and different bodies. A firm cup pops open easily from a C-fold but may be hard to compress into a labia fold. A soft cup slides in comfortably with a punch-down fold but may need some coaxing to fully expand. If you’re new to cups, start with the C-fold or punch-down, and switch to the 7-fold or labia fold if you need a smaller insertion point. Most people land on their preferred fold within two or three cycles.
Cleaning Before and After Folding
Always wash your hands and the cup with warm water and a gentle, unscented soap before folding and inserting. Between periods, most brands recommend boiling the cup to sterilize it. A lab study testing bacteria removal found that steeping a cup in freshly boiled water for at least five minutes was effective, meaning you don’t necessarily need to keep a pot at a rolling boil the entire time. Pour boiling water over the cup in a mug, cover it, and let it steep for five to ten minutes. This keeps the cup clean without putting unnecessary stress on the silicone.