A. The condom should fit snugly but not just over the tip of the penis; it should cover the entire shaft. B. Condoms provide protection against sexually transmitted diseases (STDs) and should be used in addition to implanted contraceptive methods (such as IUDs or implants) to prevent the spread of STDs. Implanted contraceptives do not offer STD protection. C. Spermicides can increase condom effectiveness, but condoms are not equally effective with or without them. Their effectiveness varies. D. Petroleum-based lubricants can degrade latex condoms and increase the risk of breakage, so water-based or silicone-based lubricants are recommended.