With one hand separate the lips of your vagina and with the other squeeze the rim of the cap together firmly and put it into the vagina. Push the cap along the bottom wall of the vagina tipping the cap so the mouth or open part is facing toward the back, aiming for the cervix. Now pinch the dome end of the cap between your second and third fingers and continue pushing it towards your cervix. If you stop pushing midway, the cap may suction onto the vaginal wall instead of the cervix. When the cap gets near the cervix, it should go on easily.
Most women feel nothing as it slips on, but a few women can tell when it takes hold.
Press the rim of the cap around the cervix and pinch the rounded dome end of the cap to help establish the suction that helps hold it in place. Check to see if the cervix is covered by pressing on the dome of the cap, then sweep your finger all around the cap. The cervix should be completely covered. Check the suction by tugging on the cap. If the cap is not in the right place, try to push it onto the cervix or take it out and try again.