CHAPTER 17 - Cervical Caps: Only the Essentials Key Points for Providers and Clients The cervical cap is placed deep in the vagina before sex. It covers the cervix. Requires correct use with every act of sex for greatest effectiveness. Used together with spermicide to improve effectiveness. What Is the Cervical Cap? A soft, deep, latex or plastic rubber cup that snugly covers the cervix. Comes in different sizes; requires fitting by a specifically trained provider.