Sex, is both a noun and a verb. Sex - the noun - refers to male and female components needed for sexual reproduction, and is quite different from gender. Sex refers to the biological and physiological characteristics that define men and women. Gender refers to the socially constructed roles, behaviors, activities, and attributes that a given society considers appropriate for men (masculine) and women (feminine).
Sex as a verb refers to any action capable of provoking an orgasm. Heterosexual means an act involving a male and female. Homosexual refers to sexual acts between partners of the same sex. There are multiple ways to enjoy sexual encounters, including ways that are likely to provoke pregnancy and ways that invoke transitory pleasure.
Sexually Transmitted Infections (STIs) may be contracted during unprotected sexual contact. STIs can reduce fertility, cause death or serious health risk, and should be taken care of immediately by a health care professional. See Sexually Transmitted Diseases for more information.
Many people use the word "sex" to refer to vaginal intercourse.
Vaginal intercourse can be defined as the penetration of the vaginal cavity. In a heterosexual context, vaginal intercourse occurs when a penis enters a vagina. In this case, the biological purpose of penile penetration of a vagina is to implant semen and provoke the conception of a fetus. However, the intention of heterosexual vaginal intercourse does not have to be conception. Likewise, homosexual vaginal intercourse, or sex between two women, can be accomplished with the use of fingers, hands or sex toys. Between queer individuals no standard definition of sex can be applied, as sex can take on any form of physical pleasure.
A vaginal cavity usually produces adequate lubrication for the act, but additional lubrication may be needed, particularly for older women. Only water-based lubricants intended for that purpose should be used, as other lubricants can cause irritation and may reduce the effectiveness of any barrier-method contraceptive used. Some lubricants are neutral whilst others explicitly have spermicide to reduce the possibility of conception. It is important to note that even small quantities of semen splashed near the vagina can occasionally provoke pregnancy without actual penetration having occurred.
Anal sex can be defined as an object entering an anal cavity in order to provide pleasure. The anus does not produce natural lubrication as the vagina does, so lubricant should always be used when engaging in anal intercourse. Also, the lining of the rectum is not as strong as the lining of the vaginal canal, so vigorous sex can cause rips and tears in the lining of the rectum. For this reason, plenty of lubrication should always be used, and partners should proceed carefully.
When engaging in anal sex, a condom should always be worn to prevent the bacteria from the digestive tract from entering the urethra of the penis. These bacteria can cause dangerous infections in an exposed penis. Also, STIs from the penis can be quickly absorbed through the thin membrane of the rectum. When using hands or fingers to engage in anal penetration, be sure to wear well-fitting sterile gloves, and change gloves between sexual acts to ensure maximum safety.
Oral sex occurs when the genitals of one partner are stimulated by the mouth, lips, and tongue of the other partner. When oral sex is performed on a man, it is called fellatio, and when it is performed on a woman, it is called cunnilingus. When performing oral sex, care should be taken not to touch your teeth to your partners genitals, because those sensations are typically unpleasant.
During fellatio, the man should wear a condom to prevent the transmission of disease into the mouth of his partner. During cunnilingus, a dental dam can be used for the same purpose. A dental dam is a thin sheet of plastic or latex which goes over the genitals, to prevent direct fluid contact, and thus prevent the spread of disease. A condom may be unrolled, cut along one side, and spread open to be used in place of a dental dam. Plastic cling wrap that is not microwave safe may also be used in place of a dental dam.
In addition to the actions described above, people can also use their hands to stimulate the genitals of their partners. Manual sex is a reasonably safe sexual contact technique in that the hand has no mucous membranes (like the mouth, anus, and vagina have), and therefore are less likely to transmit or contract STIs. If the hand has open wounds on it, however, diseases can be passed directly to and from the bloodstream.
Before touching another person's genitals with your hand, make sure to wash your hand with plenty of soap and water.
In some cultures sex is regarded as 'dirty'. In fact it is important to protect the body from infection, so frequent washing is appropriate as a primary measure. Washing alone, although vitally important, can not provide complete protection from sexually transmitted diseases. Washing can usefully form part of pre and post sexual activity for both partners.
Any object inserted into the anus (dildo, hand, penis, etc) should be clean, and never subsequently be inserted directly into a mouth or a vagina. The rectum is intended to eliminate body wastes, and so contains a large number of bacteria that can be transmitted to the mouth or vagina, and cause infection. An object that has been in an anus should be washed with soap and water immediately afterwards.
Oral, anal, and vaginal contact with an unprotected penis can all spread STIs, so a condom should be used. Condoms and dental dams should be used to prevent the mucous membranes of the genitals, mouth, and anus from coming into contact with body fluids which may bear infection (saliva, semen, naturally produced sexual lubricant, blood etc. )
A hand, used for so many activities, can be especially dirty, and may well carry bacteria unless carefully cleaned. Washing may seem obvious, but disclosing soap (which changes color) is used to train medical staff to wash themselves properly! Inserting a hand into the anus, vagina, or mouth of a partner can easily cause infection. Touching the head of a penis, especially around the urethral opening can also spread disease. Careful and thorough washing with soap and water before any sexual activity such as touching, fondling, and manual stimulation is important to minimize such risks.