1) Wash your hands thoroughly.
2) Take a deep breath and relax your vaginal muscles. If you are tense down there, you will have a hard time inserting the cup.
3) Apply water or water-based lube to the rim of the cup.
4) Tightly fold the menstrual cup in half (or use punch down fold), and hold in one hand with the rim facing up.
5) Insert the cup; imagine you insert a tampon without an applicator. It should sit a few inches below your cervix.
6) Once the cup is fully in, rotate it, to get the cup to open. You can also pinch at the base, and keep pushing and twisting it gently until the cup opens.
This is crucial, as you want the cup to open, to create an airtight seal that will prevent any leaks.