What is oral sex?

Introduction

Oral sex is the sexual stimulation of the genitalia (of consenting adults) by using the mouth and/or tongue. This can occur by a man or a woman stimulating themselves (very hard to do but it can be done by a small number of very flexible people), or it can be, most commonly, done by the stimulation of the genitals of one person by the mouth, lips or tongue of another person.

Types of Oral Sex

Cunnilingus

Cunnilingus is one of the types of oral sex that involves the sexual stimulation of one or more of the labia, clitoris, urethra and/or vulva of a woman by using the mouth, lips and/or tongue of a sexual partner (or themselves, if possible). A sexual partner performing cunnilingus can be of either gender, or could even be transgendered.
Cunnilingus is performed by licking, sucking and gentle nibbling on the clitoris, outer lips, inner vagina and urethra (pee hole) of the woman. Some women prefer a gentle steady approach whilst others like a rough, frenzied approach. Like with all sexual activities it is best to ask your partner what they like best and to also discuss what you are comfortable doing and what you are not. Stimulation can also occur with the hand at the same time as oral stimulation.

Slang Terms for Cunnilingus

Eating out, eating pussy, sucking pussy, sucking clit, eating "hair pie". (amongst others)

Fellatio

Fellatio is the sexual stimulation of the penis (shaft, glans and urethra of a man by a sexual partner (or themselves, if possible). A sexual partner performing fellatio can be of either gender, or could even be transgendered.
Fellatio is performed by sucking on the head of the penis, licking the shaft and/or by sucking the penis whilst moving your head up and down in a pumping action. Some men like a gentle approach, others prefer a rougher approach that provides almost constant sucking on the penis whilst moving up and down the shaft. Most men will ejaculate at the end of oral sex and it is important for the pleasure and comfort of both partners to understand that this will happen and to be prepared to deal with it. Many men prefer their partner to receive the cum in their mouths and swallow it, others don't have a preference or leave it up to the partner. Stimulation with the hand can also occur at the same time as oral stimulation.

Slang Terms for Fellatio

Blow job, sucking cock, sucking off, playing the skin flute, suck job. (amongst others)

Other forms of Oral Sex

Scrotal/Testicular stimulation

This is the oral sexual stimulation of the man's scrotum (bag/sack) and/or his testes (balls/nuts).

Slang Terms for Scrotal/Testes stimulation

Tea-bagging, sucking nuts. (amongst others)

Anal stimulation

Stimulation of the anus by use of the oral organs is also quite common and involves the licking around and within the opening for feces.

Slang Terms for Anal/Oral stimulation

Rimming, rim-job, star-fishing, brown-holeing. (amongst others)

Feelings of Oral Sex

Oral sex is described often as very pleasurable, both by men and women.

Sexual Health and Oral Sex

Sexually Transmitted Diseases can be transferred by oral sex. Both the sperm and semen of a man and the vaginal fluid of a woman can contain bacteria and viruses that can cause an STD. The risk of HIV transmission by oral sex is relatively low compared to other methods of transmission. A partner receiving a woman's vaginal fluid or a man's cum (sperm/semen) in their mouths and either spitting it out or swallowing it would most likely not receive the HIV virus unless they had cuts (or recent dental work) in their mouths and their partner were positive for HIV in the first place (of course).
Anal/oral sex can transmit bacteria from the anus to the penis/vagina if it is done prior to stimulating the penis/vagina with the mouth. It is best to avoid anal stimulation if the intention is to then stimulate the penis or the vagina orally. The transmitted bacteria can cause disease, although this is lowered dramatically if a through washing of the sex organs takes place before and after sex.

Safer Sex

It is important to consider whether the usage of condoms or dental dams is appropriate. A condom is a latex closed ended tube that covers the man's penis and protects him from his partner's saliva and his partner from his bodily fluids. A dental dam is a sheet of latex that is held in place over the woman's vulva (vagina) and her partner then licks and/or sucks her genitalia through the latex. Both condoms and dental dams come in flavors such as mint, chocolate, strawberry, grape, bubble-gum etc.
Factors to consider when deciding on use of safer sex techniques are: length of time with partner, partners (and your) sexual health and history, recent cuts and/or dental work done. One night stands are a strong indicator of a need to use protection, whereas having lived with your partner for years may be a reason to not use safer sex techniques.

Pregnancy

Pregnancy requires that a man's sperm comes into contact with a woman's egg (or ovum). For this to occur, sperm has to come into contact with the vagina or the area immediately surrounding the vagina. As such, oral sex does not lead to pregnancy by itself, but if cum drips from the penis or mouth and comes into contact with the vagina (even the outside) it can lead to pregnancy.

Hygiene, Smells, Tastes and Oral Sex

It is frequently a complaint of people who would like to try oral sex but don't that the taste or smell they receive from their partner is a turn-off. It is important to wash prior to oral sex if this is a concern. The genitals often have a natural musky smell to them and this can be very much lessened by washing. The bodily fluids have a natural taste that cannot be affected by washing; a man's cum is most often thought to taste like a bland, slightly salty egg-white like substance with little objectionable smell, whereas a woman's vaginal fluid is frequently described as thinner, sweeter, slightly salting and quite sticky.
To sum up ;
Oral sex is when the mouth is used to stimulate either your own or a partners genitalia/sexual organs.