Proper sex education requires knowledge of terminology associated with sex. The Language of Sex part I, covered terms from A-H. Today, the alphabet is completed from I to Z. Source: The A-Z of Sexual Terms Glossary and Sex Encyclopaedia.

Impotence: A man's inability to achieve or maintain an erection firm enough to penetrate during intercourse. Also known as erectile dysfunction or erectile inhibition, this is an automatic process and a man will experience difficulty getting or maintaining an erection because the blood that should flow into the penis and engorge it, making it firm and erect, fails, even though the man may feel excited and stimulated.

Incest: A taboo in almost all societies, incest refers to sexual contact between close blood relatives for whom such behaviour is forbidden by law, custom or religion.

Indigo: A sexually transmitted infection which affects the liver and is caught through sexual activities like rimming, or by sharing infected needles.

Jap's eye: Slang term for the small opening at the end of a man's penis where urine and sperm come out.

Jism: Another word for semen or sperm.

Labia: The flaps of skin on both sides of a woman's vagina.

Lesbian: A woman who engages in sexual activity with other women.

Libido: Another word for sex drive.

Licking out: When the mouth and tongue are used to stimulate or pleasure a woman's vagina, also called oral sex or cunnilingus.

Masturbate: Touching or stimulating one's body and genitals or someone else's genitals for sexual pleasure. Masturbation is a natural and normal way of exploring your own body. Also known as wanking.

Mini-Pill: Also known as the progestogen-only Pill which prevents pregnancy by changing a woman's mucus so sperm cannot swim to reach the egg.

Miscarriage: When a foetus (unborn baby), comes out of a woman's womb before it is old enough to survive outside its mother's body. Also called 'losing a baby'.

Morning-after pills: Another name for emergency contraceptive pills. Taken up to 72 hours after unprotected sex, the morning-after pill prevents pregnancy.

Non-specific urethritis: A sexually transmitted infection that only affects men.

One-night stand: Having casual sex with someone without going into a relationship with them.

Oral sex: Using the mouth and tongue to pleasure and stimulate a man's penis or a woman's vagina. There are contraceptives available to avoid catching STIs through oral sex, such as Dental Dams and condoms.

Orgasm: The peak of sexual pleasure, orgasms are different for everyone and not everyone has an orgasm every time he has sex.

Ovulation: Once a month, or once during each menstrual cycle, a woman's ovaries release an egg. This is called ovulation.

Pedophilia: When a adult has unlawful sex with a child under 16 years old, He or she is known as a pedophile.

Pelvic inflammatory disease: A disease affecting girls which causes pain in the lower abdomen. It can lead to an increased risk of ectopic pregnancy and infertility.

Penetrative sex: When the vagina or anus is penetrated by a penis or an object, such as a dildo or another sex toy.

Period: Once a woman reaches puberty, she will have a menstrual bleed, or period, each month. The bleeding happens when an egg is not fertilised and comes out of the vagina along with the thick lining of the womb that builds up each month. The blood usually looks thick and may be bright red or brown in colour.

PMS/PMT: Short for pre-menstrual syndrome or pre-menstrual tension, it is caused by hormonal changes in the body during the days leading up to a female's period. It can make some females feel moody, sad, irritable and tired.

Pornography: Films, books or pictures that are made to make you feel sexually excited or aroused.

Premature ejaculation: When a man ejaculates too soon or before he wants to. This may be caused by over-excitement, performance anxiety, and inexperience, among other causes.

Puberty: The time when the bodies of girls and boys start to change and become sexually mature. Puberty usually starts between the ages of 9 and 13, but some may start younger or older. Puberty takes a long time and affects children emotionally as well as physically. Puberty is triggered by certain hormones and chemicals in the body.

Pubic lice: Pubic lice are tiny insects that live on the skin and are often called 'crabs'. They are passed on during sex or through close physical contact.

Rhythm method: An unreliable method of contraception that depends on working out the times of the month when a woman is not ovulating.

Rimming: Using the mouth and tongue to stimulate or pleasure another person's anus. Occasionally, it can lead to serious gut infections and may lead to hepatitis .

Scabies: An itchy and contagious skin infection that can be passed on through non-sexual and sexual contact, even holding hands.

Scrotum: The bag of skin that holds a man's testicles.

Semen: A fluid that contains a mixture of secretions from a man's reproductive glands and sperm cells. Semen comes out from the man's penis when he ejaculates.

Sexual development: Also called puberty. The time when your body develops sexually.

Sexual history: All the persons you have had a sexual relationships with during your life.