You can check that your cup is fully open in 1 of 3 ways:
1. Gently press your index finger on one side of your vaginal wall to create space for the cup to open.
2. Run your index finger around the base of the cup to feel if there are indents or pleats (which mean it hasn’t opened all the way).
3. Grab the base of the cup and rotate it one direction or the other.