A male condom is a thin sheath put over an erect penis. When left in place during sex, oral sex, or anal sex, male condoms are a very effective way to shield yourself and your partner from sexually transmitted diseases (STDs), for example, HIV. Additionally, male condoms are also a powerful way to forestall pregnancy. Condoms, also known as rubbers, are generally made of latex, however, some are produced using polyurethane or lambskin. Latex and polyurethane condoms give the most protection against STDs.