A condom is a device most commonly used during sexual intercourse. It is put on a man's erect penis and physically blocks ejaculated semen from entering the body of a sexual partner. Condoms are used to prevent transmission of sexually transmitted diseases (STDs—such as gonorrhea, syphilis, and HIV) and pregnancy. Because condoms are waterproof, elastic, and durable, they are also used in a variety of secondary applications. These range from creating waterproof microphones to protecting rifle barrels from clogging. Foot travelers in Amazonic South America wear condoms when wading through water to prevent a small catfish known as candirú from swimming into the urethra. The fish is attracted to the scent of blood and urine
What is generally called a condom is the 'male' condom, a sheath or covering which fits over a man's penis, and which is closed at one end. There is also now a female condom, or vaginal sheath, which is used by a woman and which fits inside her vagina. Below is about the male condom.
Condoms are usually made of latex or polyurethane. If possible you should use a latex condom, as they are slightly more reliable, and in most countries they are most readily available. Latex condoms can only be used with water based lubricants, not oil based lubricants such as Vaseline or cold cream as they break down the latex. A small number of people have an allergic reaction to latex and can use polyurethane condoms instead. Polyurethane condoms are made of a type of plastic. They are thinner than latex condoms, and so they increase sensitivity and are more agreeable in feel and appearance to some users. They are more expensive than latex condoms and slightly less flexible so more lubrication may be needed. However both oil and water based lubricants can be used with them. Some condoms are not lubricated at all.
You need to use a new condom every time you have sexual intercourse. Never use the same condom twice. Put the condom on after the penis is erect and before any contact is made between the penis and any part of the partner's body. If you go from anal intercourse to vaginal intercourse, you should consider changing the condom.
Condoms have an expiration (Exp) or manufacture (MFG) date on the box or individual package that tells you when it is safe to use the condom until. It's important to check this when you use a condom. You should also make sure the package and the condom appear to be in good condition.
Condoms can deteriorate if not stored properly as they are affected by both heat and light. So it's best not to use a condom that has been stored in your back pocket, your wallet, or the glove compartment of your car. If a condom feels sticky or very dry you shouldn't use it as the packaging has probably been damaged.
If used properly, a condom is very effective at reducing the risk of being infected with HIV during sexual intercourse. Using a condom also provides protection against other sexually transmitted diseases, and protection against pregnancy. In the laboratory, latex condoms are very effective at blocking transmission of HIV because the pores in latex condoms are too small to allow the virus to pass through. However, outside of the laboratory condoms are less effective because people do not always use condoms properly.
If there is question: Don't you trust me? Then answer: Trust isn't the point, people can have infections without realising it. If, I'm on the pill, you don't need a condom, answer: I'd like to use it anyway. It will help to protect us from infections we may not realise we have. If asked: I will pull out in time, answer: Women can get STDs and get pregnant from pre-ejaculate
Condoms are the only contraceptive that help prevent the spread of sexually transmitted diseases (including HIV) and both pregnancy when used properly and consistently. Condoms are one of the most reliable methods of birth control when use properly and consistently. Condoms have none of the medical side-effects of some other birth control methods may have.