A form of sexual assault where one person psychologically or physically coerces another to engage in one or more sexual acts against their will or without their consent. Date rape is also known as acquaintance rape and is committed by someone the victim knows. In some cases, drugs like GHB and Rohypnol—commonly referred to as “date rape” drug—are given to the victim without their knowledge before the rape, leading to unconsciousness and memory loss. Laws vary by state in regard to sexual assault and the use of “date rape” drugs.

A fellatio technique, in which one person takes the entire shaft of another person's erect penis into the mouth and throat. Deepthroating is likely to trigger the gag reflex, and is not considered a traditional part of fellatio. A 1972 movie by the same name popularized the technique.

A type of sexual dysfunction in which a man is unable to ejaculate during an erection after more than 30 minutes of sexual activity. Men who choose to wait to ejaculate, whether for their own pleasure or a partner's, do not have delayed ejaculation. If a man has never ejaculated, a doctor will examine him for a congenital or physical cause. More often, delayed ejaculation may be caused by: performance anxiety; depression and/or the use of anti-depressants; too rough or too frequent masturbation; negative or traumatic sexuality education growing up; concerns about impregnating a partner; and substance abuse and addiction. Delayed ejaculation also may occur as a result of health conditions like diabetes and prostate cancer. Treatment focuses on any underlying physical problems and, often, individual therapy, sex therapy or couples therapy. (see inhibited orgasm)

A thin latex sheath designed to be used during dental work that may also be used during cunnilingus or rimming to reduce the risk of STI transmission. A dental dam is placed over the vulva and/or anus.

A hormonal method of birth control that uses an injection of synthetic progesterone to prevent ovulation and, therefore, pregnancy. Depo-Provera is administered by a doctor or healthcare provider and protects against pregnancy for three months. Benefits of Depo-Provera include: convenience; contains no estrogen; fewer periods over time; less menstrual cramping and pain; and protection against pelvic inflammatory disease, ovarian cancer and uterine cancer. Side effects may include: spotting or heavy vaginal bleeding; weight gain; delay in return to fertility; and increased risk of osteoporosis, perhaps indefinitely. Side effects may persist in some women for up to 6-18 months after the final shot. Depo-Provera is close to 100% effective for the prevention of pregnancy, but does not protect against STIs.

A psychiatric disorder that may be mild, moderate or severe, and may be characterized by: an inability to concentrate; insomnia; loss of appetite; lack of pleasure; feelings of extreme sadness, guilt, helplessness and hopelessness; and, in extreme cases, thoughts of death. Depression is sometimes accompanied by anxiety. Depression may be associated with problems related to libido, arousal, orgasm and emotional intimacy. Commonly prescribed medications for depression include anti-depressants and sedatives, which may cause additional side effects. In addition to medication, depression may be treated in individual therapy and sex therapy, depending on the nature of the problem.

Short for dehydroepiandrosterone, a hormone secreted by the adrenal glands that is a precursor to estrogen and testosterone. DHEA plays an important role in libido, energy levels and certain diseases. DHEA levels begin to decline after age 30, but the value of DHEA supplements is unclear and potentially poses health risks.

A disease in which the body does not produce or properly use insulin, a hormone that converts food into energy. Diabetes may cause problems related to arousal, libido, genital sensation, erectile dysfunction, retrograde ejaculation and vaginitis.

A barrier method of birth control that uses a dome-shaped latex cup to cover the cervix to prevent pregnancy. A diaphragm is used with spermicide to prevent sperm from entering the uterus. Benefits of a diaphragm include: it is temporary, non-hormonal and requires no interruption of sex play if inserted beforehand. Side effects may include: irritation or infection from the diaphragm and/or spermicide; difficulty with insertion; and the chance that it will move out of place during sex. A diaphragm provides no protection against STIs. Diaphragms may require refitting when a woman has experienced pregnancy, childbirth or weight gain.

A smooth device designed to gently stretch the opening of the vagina. Dilators are often sold in sets, with increasing sizes to progressively ease penetration. Dilators may be used to treat vaginismus, dyspareunia and vaginal narrowing, as well as after certain gynecological surgeries. Some women use dilators as dildos for arousal, masturbation and orgasm. Dilators may be provided to a woman from a sex therapist or healthcare provider, or may be independently purchased.

A type of non-vibrating sex toy designed for penetration of the vagina or anus. Dildos vary widely in size, texture, appearance and material. Dildos can be made of acrylic, glass, metal, plastic, rubber or silicone. A dildo may be used by men or women, during any type of sex play, foreplay, intercourse, oral sex or masturbation, including by women who enjoy or are curious about double penetration and women or men who enjoy or are curious about anal stimulation. G-spot vibrators/dildos are designed for G-spot stimulation.

A form of fantasy or foreplay in which a couple talks explicitly about sex.

See vaginal discharge

(1929-present) An American sex educator, author and early advocate for women's pleasure and body-awareness through masturbation, which she has frequently referred to as "self-loving." Considered the "grandmother of masturbation," Dodson is famous for holding workshops that promote masturbation and positive genital self-image.

See rear entry

A relationship that is recognized by law for couples who are not married or cannot legally marry as a result of their sexual orientation. Domestic partnership legislation varies by city and state, and provides some of the rights and benefits offered to married couples.

(a.k.a., domme) A woman who takes the dominant role in BDSM activities. A dominatrix usually acts out a fantasy or fetish with a submissive.

See dominatrix

One or more ova that are retrieved from a woman's ovaries to allow another woman to achieve pregnancy. Donor eggs are generally fertilized in the laboratory with sperm, either from a partner or a sperm donor, using in vitro fertilization, then placed in a woman's uterus. Donor eggs may be used in cases of of premature menopause, advanced age or a lack of response to other infertility treatment.

A neurotransmitter that regulates movement and emotion, and contributes to feelings of pleasure. Some research suggests that dopamine may be released in large quantities during the lust phase and infatuation phase of a new relationship, fueling arousal, libido and orgasm ability. Dopamine also plays a role in addiction.

Simultaneous penetration of the vagina and the anus, typically achieved with some combination of a penis, finger or sex toys, such as vibrators, dildos, anal plugs, anal vibrators or strap-ons. In the pornography industry, double penetration typically refers to two men simultaneously penetrating a woman.

A solution used to wash the vagina for hygienic reasons. Many women douche after a period, after sexual activity, or to wash away excess vaginal discharge or improve vaginal odor. Douching is generally not recommended, since it disrupts the natural bacteria balance in the vagina and may increase a woman's risk of developing infections such as bacterial vaginosis, STIs and pelvic inflammatory disease.

When a male experiences orgasm without ejaculation. Orgasm and ejaculation are two separate processes that often occur simultaneously. However, a dry orgasm can also occur before puberty, and in males who experience retrograde ejaculation.

Painful menstrual periods, which affect nearly half of women. Symptoms may include aching and cramping in the lower abdomen or lower back, which may be the result of contractions of the uterus. Unusual or excessive pain may be a sign of pelvic inflammatory disease, uterine fibroids or endometriosis.

A type of sexual dysfunction in which a woman experiences recurrent or persistent pain with vaginal intercourse, which results in personal distress. The pain can be in the vagina or deep inside the pelvis. The cause of dyspareunia is not always known; however it may be associated with: past abuse or rape; negative sexuality education; and anxiety and depression. Perhaps more often, dyspareunia may be the result of another condition, such as: vaginitis or an STI; vaginal dryness; atrophic vaginitis; endometriosis; lichen schlerosis; vulvodynia or a retroverted uterus. It also may occur after childbirth or an episiotemy, or around the time of menopause because of declining estrogen levels. Treatment focuses on any underlying physical problems and, often, sex therapy to re-educate a woman in her body and couples therapy to improve communication.