Erection in the context of "Sexual intercourse"

In Greek mythology, a satyr (Ancient Greek: σάτυρος, romanized: sátyros, pronounced [sátyros]), also known as a silenus or silenos (Ancient Greek: σειληνός, romanized: seilēnós [seːlɛːnós]), and sileni (plural), is a male nature spirit with ears and a tail resembling those of a horse, as well as a permanent, exaggerated erection. Early artistic representations sometimes include horse-like legs, but, by the sixth century BC, they were more often represented with human legs. Comically hideous, they have mane-like hair, bestial faces, and snub noses and they always are shown naked. Satyrs were characterized by their ribaldry and were known as lovers of wine, music, dancing, and women. They were companions of the god Dionysus and were believed to inhabit remote locales, such as woodlands, mountains, and pastures. They often attempted to seduce or rape nymphs and mortal women alike, usually with little success. They are sometimes shown masturbating or engaging in bestiality.

In classical Athens, satyrs made up the chorus in a genre of play known as a "satyr play", which was a parody of tragedy and known for its bawdy and obscene humor. The only complete surviving play of this genre is Cyclops by Euripides, although a significant portion of Sophocles's Ichneutae has also survived. In mythology, the satyr Marsyas is said to have challenged the god Apollo to a musical contest and been flayed alive for his hubris. Although superficially ridiculous, satyrs were also thought to possess useful knowledge, if they could be coaxed into revealing it. The satyr Silenus was the tutor of the young Dionysus, and a story from Ionia told of a silenos who gave sound advice when captured.

Penile–vaginal intercourse, or vaginal intercourse, is the insertion of an erect penis into a vagina. It is the primary form of copulation in mammals and a form of penetrative sexual intercourse in human sexuality. Synonyms are: vaginal sex, coitus (Latin: coitus per vaginam), (in elegant colloquial language) intimacy, or (poetic) lovemaking; some of which are used for other forms of intercourse as well. Cohabitation is a related term describing a living arrangement.

Various sex positions can be used. Following insertion, additional stimulation is often achieved through rhythmic pelvic thrusting or a gyration of the hips, among other techniques. The biological imperative is to achieve male ejaculation so that sperm can enter the female reproductive tract and fertilize the egg, thus beginning the next stage in human reproduction, pregnancy.

Anal sex or anal intercourse principally means the insertion and thrusting of the erect penis into a person's anus, or anus and rectum, for sexual pleasure. Other forms of anal sex include anal fingering, the use of sex toys, anilingus, and pegging. Although anal sex most commonly means penile–anal penetration, sources sometimes use anal intercourse to exclusively denote penile–anal penetration, and anal sex to denote any form of anal sexual activity, especially between pairings as opposed to anal masturbation.

While anal sex is commonly associated with male homosexuality, research shows that not all homosexual men engage in anal sex and that it is not uncommon in heterosexual relationships. Types of anal sex can also be part of lesbian sexual practices. People may experience pleasure from anal sex by stimulation of the anal nerve endings, and orgasm may be achieved through anal penetration – by indirect stimulation of the prostate in men, indirect stimulation of the clitoris or an area in the vagina (sometimes called the G-spot) in women, and other sensory nerves (especially the pudendal nerve). People may also find anal sex painful, sometimes extremely so, which may be due to psychological factors in some cases.

Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind as preparation for sexual intercourse, and continue during intercourse. Male arousal will lead to an erection, and in female arousal, the body's response is engorged sexual tissues such as nipples, clitoris, vaginal walls, and vaginal lubrication.

Mental stimuli and physical stimuli such as touch, and the internal fluctuation of hormones, can influence sexual arousal. Sexual arousal has several stages and may not lead to any actual sexual activity beyond a mental arousal and the physiological changes that accompany it. Given sufficient sexual stimulation, sexual arousal reaches its climax during an orgasm. It may also be pursued for its own sake, even in the absence of an orgasm.

Peyronie's disease (PD) is a benign, acquired penile connective tissue disease characterized by the occurrence of fibrotic plaques within the tunica albuginea — the dense elastic covering of the corpora cavernosa. The plaques cause abnormal curvature, pain, penile deformities (e.g., narrowing or indentation), and usually erectile dysfunction, particularly during erection. The condition typically leads to significant sexual and psychological effects, including difficulty with penetration and lowered self-esteem or evasiveness. Peyronie's disease is most often seen in middle-aged and older men with a median age of onset between 55 and 60 years, however it is also common in younger individuals and adolescents.

While the etiology of Peyronie's disease is still uncertain, the leading hypothesis is that it arises from dysregulated wound healing in response to chronic microtrauma of the erect penis. This triggers a cascade of profibrotic molecular pathways — most notably overexpression of transforming growth factor-beta 1 (TGF-β1) — that end in fibroblast proliferation, myofibroblast differentiation, and overproduction of type I collagen. Genetic predisposition is supported by family clustering and linkage with systemic fibrosing disorders such as Dupuytren's contracture. Risk factors include age, penile injury, diabetes mellitus, and cigarette smoking.

Ejaculation is the discharge of semen (the ejaculate; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. After forming an erection, many men emit pre-ejaculatory fluid during stimulation prior to ejaculating. Ejaculation involves involuntary contractions of the pelvic floor and is normally linked with orgasm. It is a normal part of male human sexual development.

Ejaculation can occur spontaneously during sleep (a nocturnal emission or "wet dream") or in rare cases because of prostatic disease. Anejaculation is the condition of being unable to ejaculate. Dysejaculation is an ejaculation that is painful or uncomfortable. Retrograde ejaculation is the backward flow of semen from the urethra into the bladder. Premature ejaculation happens shortly after initiating sexual activity, and hinders prolonged sexual intercourse. A vasectomy alters the composition of the ejaculate as a form of birth control.

Clitoral erection (also known as clitoral tumescence or female erection) is a physiological phenomenon where the clitoris becomes enlarged and firm.

Clitoral erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is usually, though not exclusively, associated with sexual arousal. Erections should eventually subside, and the prolonged state of clitoral erection even while not aroused is a condition that could become painful. This swelling and shrinking to a relaxed state seems linked to nitric oxide's effects on tissues in the clitoris, similar to its role in penile erection.