Attraction to the buttocks dates back to when we first started to walk upright, or earlier, and is not limited to our species. Dogs, for example, are attracted to the scent of the rear as it reveals to them much information, including the health of whoever's rear it is. Some consider well-formed buttocks to be a sexually pleasing important part of one's physical attractiveness. However, the definition of "well-formed" is up for debate, as sexual aesthetics of the buttocks vary considerably from culture to culture, per fashionable style period and even from person to person. Exposure of the buttocks in non-intimate situations may cause feelings of shame, embarrassment, or humiliation which may, however, excite exhibitionists and voyeurs.

Willfully exposing one's own bare buttocks as a protest, a provocation or for fun (as a "kick") is called mooning. Mooning someone is generally considered an act of and for the young, but some adults, especially while intoxicated have been known to practice mooning as well. On the other hand having one's bare buttocks exposed by another unexpectedly and in public, sometimes called a "pantsing", is usually a source of humiliation.

A wedgy is pulling someone's undergarments or swimming trunks up through their 'crack' to be hauled over the top of the victim's pants, sometimes partially baring the victim's buttocks. An atomic wedgy is pulling the undergarments or swimming trunks up over the victim's head. An adult (or adolescent) forced to expose or take punishment on their buttocks may seem reduced to the status of a child in cultures where public nudity below the waist and/or spanking is common only for (young) children.

It is no coincidence that the verb to spank is the only one specifically meant for physical discipline of a specific part of the body; in many punitive traditions, the buttocks are the preferential target for painful lessons, from educational to judicial, as offering them for punishment (especially divested) adds a psychological dose of embarrassment to the pain, which can be meted out with minimal risk of long term corporal harm. Thus in various cultural traditions expressions like "A black man's ears are in his buttocks" (e.g. in Uganda) or "seat of learning" clearly refer to the preferential paining of the posterior in a submissively bend and exposed position. Many comedians, writers, and others rely on the buttocks in these ways as a source of amusement, camaraderie, and fun.

It is quite common to hear phrases that make use of the buttocks as metonymy (more precisely, synecdoche) for a whole person, but generally with a negative connotation. For example, terminating an employee may be described as "firing his ass". One might say "move your ass" as an exhortation to greater haste or urgency. Expressed as a function of punishment, defeat or assault becomes "kicking one's ass". Such phrases also may be suggestive of a person's characteristics. For example, difficult people are termed "hard asses". People deemed excessively puritanical or frugal may be termed "tight asses".

Synonyms

• Aft, stern and poop, naval in origin, caboose, originally a ship's galley in wooden cabin on deck; also the "rear end" car of a freight train; considered a cute, G-rated synonym

• arse or ass, and (butt-)hole - a pars pro toto (strictly only the actual anal region); also used as an insult for a person

• Backside, posterior, behind and its derivatives (hind-quarters or the childish "hiney"),

• Badonkadonk - a colloquialism popular in Ebonic vernacular which refers specifically to the posterior of an especially curvaceous woman

• Bottom (and the shortening "bot" as well as childish diminutives "bottie" or "botty"), but the use of near-homophone booty (black slang for the female body since the 1920s) as famously by K.C. and the Sunshine Band's Shake Your Booty, is an 'artistic liberty'

• Breech, a metaphorical sense derived from on older form of the garment breeches (as the French culotte meaning pantaloons, via cul from Latin culus 'butt'), so 'bare breech' means without breeches, i.e. trouserless butt

• Bum - in British English a mild often humorous reference to buttocks, not necessarily in vulgar or sexual context; however also used in reference to

• buns, mounds and orbs - shape-metaphors, usually in the plural

• Bundas - origin derived from Portuguese. A bunda-lover is also known as a 'Bundaist'

• Buttocks - As buttocks are an object of both shame and fascination, it is not surprising that there are rather a lot of colloquial terms, euphemistic, ironic or other, to refer to them.

• Can (a container) had an unusual development: Slang meaning "toilet" is c.1900, said to be a shortening of piss-can, meaning "buttocks" from c.1910, verb meaning "fire an employee" (to flush=dump?) from 1905.

• Cheeks, a shape-metaphor within human anatomy, but also used in the singular : left cheek and right cheek; sounds particularly naughty because of the homonym and the adjective cheeky, lending themselves to word puns

• Fanny - a socially acceptable term in print, in the United States at least, for many years before some of the bolder terms came along; and a subject of jokes, since "Fanny" can be a woman's name, diminutive of "Frances". However, in British English fanny refers to the female genitals and is considered vulgar.

• Fundament (literally "foundation", not common in this general sense in English, but for the butt since 1297)

• Hams, like buttocks generally as a plural, after the meat cut from the analogous part of notably a hog; brawn, a singular, is also used for both a muscular body part (but either on arms or legs) or boar meat, especially roast

• Prat (British English, origin unknown; as in pratfall, a vaudeville term; also a term of abuse for a person)
• Rear or rear-end, derrière (French for "behind") - all strictly positional descriptions, as the inaccurate use of rump (as in 'rump roast', after a 'hot' spanking), thighs, upper legs;

• Seat (of the trousers; or metaphorically) another long-standing socially acceptable term, referring to the use for sitting - but compare the sarcastic use of seat of wisdom and similar expressions, such as 'seat of learning', referring to use as target for an 'educational' spanking.

• Tail (strictly anatomically a zoomorphism, humans only have a tail-bone; also used for the even more sensual phallus) and tail-end

• Trunk, in American English, particularly when describing large buttocks "junk in the trunk"

• Tush or tushy (from the Yiddish / Hebrew "tuchis" or "tochis" meaning "under" or "beneath")