From Pompeii In Napoli Museum (adult area!)

Sexual intercourse, or copulation or coitus, is the insertion and thrusting of a male's penis into a female's vagina for the purposes of sexual pleasure or reproduction. Other forms of penetrative sexual intercourse include anal sex, oral sex, fingering, and use of a strap-on dildo.

Sexual intercourse commonly plays a strong role in human bonding, usually being used solely for pleasure and often leading to stronger emotional bonds, and there are a variety of views concerning what constitutes sexual intercourse or other sexual activity. For example, non-penetrative sex (such as non-penetrative cunnilingus) has been referred to as "outercourse", but may also be among the sexual acts contributing to human bonding and considered sexual intercourse. The term sex, often a shorthand for sexual intercourse, can mean any form of sexual activity. Because individuals can be at risk of contracting sexually transmitted infections during these activities, though the transmission risk is significantly reduced during non-penetrative sex, safe sex practices are advised.

In human societies, some jurisdictions have placed various restrictive laws against certain sexual activities, such as sex with minors, incest, extramarital sex, position-of-trust sex, prostitution, sodomy, public lewdness, rape, and zoophilia. Religious beliefs can play a role in decisions about sex, or its purpose, as well; for example, beliefs about what sexual acts constitute virginity loss or the decision to make a virginity pledge. Some sections of Christianity commonly view sexual activity between a married couple for the purpose of reproduction as holy, while other sections may not. Modern Judaism and Islam view sexual intercourse between husband and wife as a spiritual and edifying action. Hinduism and Buddhism views on sexuality have differing interpretations.

The human penis is an external sexual organ of male humans. It is a reproductive, intromittent organ that additionally serves as the urinal duct. The main parts are the root of the penis (radix): It is the attached part, consisting of the bulb of penis in the middle and the crus of penis, one on either side of the bulb; the body of the penis (corpus); and the epithelium of the penis consists of the shaft skin, the foreskin, and the preputial mucosa on the inside of the foreskin and covering the glans penis.

The human penis is made up of three columns of tissue: two corpora cavernosa lie next to each other on the dorsal side and one corpus spongiosum lies between them on the ventral side. The urethra, which is the last part of the urinary tract, traverses the corpus spongiosum, and its opening, known as the meatus /miːˈeɪtəs/, lies on the tip of the glans penis. It is a passage both for urine and for the ejaculation of semen.

Penis (plural penises or penes) is a general term for the organs with which male and hermaphrodite animals introduce sperm into receptive females during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penes in the various species are not necessarily homologous. For example, the penis of a mammal is at most analogous to the penis of a male insect or barnacle.

The term penis applies to many reproductive intromittent organs, but not to all; for example the intromittent organ of most cephalopoda is the hectocotylus, a specialised arm, and male spiders use their pedipalps.

In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female^{[citation needed]}, but in the placental mammals the penis bears the distal part of the urethra, which discharges both urine during urination and semen during copulation as the occasion requires.

An erection (clinically: penile erection or penile tumescence; informal/slang: stiffy, hard-on, boner and many others) is a physiological phenomenon of the male genitalia of many species, in which the penis becomes firmer, engorged and enlarged. Penile 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 or sexual attraction. The shape, angle and direction of an erection varies considerably in humans.

Physiologically, erection is triggered by the parasympathetic division of the autonomic nervous system (ANS), causing nitric oxide (a vasodilator) levels to rise in the trabecular arteries and smooth muscle of the penis. The arteries dilate causing the corpora cavernosa of the penis (and to a lesser extent the corpora spongiosum) to fill with blood; simultaneously the ischiocavernosus and bulbospongiosus muscles compress the veins of the corpora cavernosa restricting the egress and circulation of this blood. Erection subsides when parasympathetic activity reduces to baseline.

The term Secret Museum or Secret Cabinet (Gabinetto Segreto) principally refers to the collection of erotic or sexually explicit finds from Pompeii, held in separate galleries in the Naples National Archaeological Museum, Naples, Italy, the former Museo Borbonico. The British Museum also contained secret rooms.

Throughout ancient Pompeii, erotic frescoes, depictions of the god Priapus, sexually explicit symbols, inscriptions, and even household items (such as phallic oil lamps) were found. Ancient Roman culture had a different sense of shame for sexuality, and viewed sexually explicit material very differently to most present-day cultures. Ideas about obscenity developed from the 18th century to the present day into a modern concept of pornography. Although the excavation of Pompeii was initially an Enlightenment project, once artifacts were classified through a new method of taxonomy, those deemed obscene and unsuitable for the general public were termed pornography and in 1821 they were locked away in a Secret Museum. For good measure, the doorway was bricked up in 1849. At Pompeii, locked metal cabinets were constructed over erotic frescos, which could be shown, for a modest additional fee, to gentlemen but not to ladies. This peep show was still in operation at Pompeii in the 1960s. The cabinet was only accessible to "people of mature age and respected morals", which in practice meant only educated males. The catalogue of the secret museum was also a form of censorship, where engravings and descriptive texts played down the content of the room.