Female condoms are made of thin, soft synthetic latex and worn inside the vagina during sex to prevent sperm from reaching the egg. They function as an intravaginal barrier by preventing contact between sperm and the egg. To use one, insert it into the vagina before sex and ensure the penis is placed inside the condom, not between it and the vaginal wall. Female condoms are 95% effective against pregnancy when used correctly and offer protection from STIs, but can be less effective if the penis touches the vaginal area before insertion, the condom is pushed too far inside, or is damaged during use.