Inserting a menstrual cup is similar to inserting a tampon. First, wash your hands.
Then, fold your menstrual cup to make it smaller.
While squatting or standing with one foot on the floor and the other on a toilet or bath tub, slowly push the folded cup into your vagina. This should be done at about a 45 degree angle as your vagina is angled and not straight-up inside your body.
The cup should pop open and unfold inside your vagina, which creates a light seal against the vaginal walls. Make sure the cup is unfolded so blood does not seep out around it. You can check by running one finger around the base - it should be round or oval. If the cup does not feel like it has opened fully, grab the stem and give the cup a small turn, which should usually do the trick.
If correctly inserted, the cup should not leak or cause any discomfort, as with a tampon. Push it in until you're comfortable; this depends on how low your cervix is, which varies from person to person. The cup can be worn low in the vagina. During the course of the day, the cup may migrate upwards and sit against the cervix. The cup can be worn up to 12 hours, depending on your flow.
The stem on the bottom of the cup can be used to find your cup when you want to remove it. (The stem can be trimmed down to whatever length you're most comfortable with.) Simply pulling on the stem is not recommended to remove the cup, as pulling it down will create suction. Reach up to the stem of the cup in order to find the base. Using your index finger and thumb, pinch the base to release the seal. Gently and slowly ease the cup out of your vagina. Empty the contents of the cup, rinse/wipe and reinsert.
When your period is over, wash your cup thoroughly and store it in its bag for proper ventilation. Never store the cup in an airtight plastic container or bag.
Take good care of your cup, and it can last you for years!