What is Butt Crack?

Definition

Butt crack (also known as the intergluteal cleft, the natal cleft, or, in British English, the bum crack) is the vertical groove between the two buttocks, extending from the coccyx to the perineum. In everyday slang, the term is almost never used clinically. Instead, it functions as a cultural shorthand for a specific visual phenomenon: the accidental exposure of this cleft above the waistband of pants, shorts, or underwear, commonly known as a plumber’s crack or builder’s bum. This exposure occurs when a person’s pants slip down while they are bending, crouching, or kneeling, revealing a strip of skin and the top of the cleft. The image is so universally recognized that it has become a staple of comedy, cartoon imagery, and workplace humor. The term “butt crack” also carries a secondary, playful meaning: the cleft itself, as a body part, is sometimes referenced in childish humor, insults, or jokes about bodily functions. It is one of the most durable sources of humor in English precisely because it is both taboo and universal—everyone has one, and everyone knows what it looks like when exposed.

Why It Matters

The butt crack matters because it occupies a unique position in the comedy of the body: it is both utterly ordinary and deeply embarrassing. The “plumber’s crack” stereotype—a tradesperson bent over, unaware that their pants have slipped—has become so iconic that it is recognized across cultures and generations. It matters, too, because it reveals something about how we see bodies and labor. The butt crack is funny when it belongs to a worker; it is mortifying when it belongs to ourselves. This asymmetry is the engine of its comedy. The exposed butt crack is a moment of unintended vulnerability, a brief glitch in the social presentation of the self. In an era of carefully curated Instagram bodies and filtered selfies, the accidental butt crack is a reminder that human bodies are unruly, imperfect, and occasionally hilarious. The term also matters in fashion and design discourse: the “low-rise” trend of the 1990s and 2000s deliberately exposed the butt crack as a style choice, transforming an accident into an aesthetic. This deliberate exposure—seen on celebrities, in music videos, and on runways—was both celebrated and condemned, revealing cultural anxieties about bodies, class, and propriety.

Example

> The plumber knelt under the sink, wrench in hand, focused on the pipe that had been leaking for three days. He did not notice that his belt, worn loosely after thirty years of the same lunch break, had slipped. He did not notice that his shirt, too short for his frame since he bought it in 2014, had ridden up. He did not notice that Mrs. Henderson, standing in the kitchen doorway with her tea, was looking at something other than his craftsmanship. When he finally emerged, grease on his hands and triumph on his face, she said nothing. She simply handed him a check and a business card for a tailor. He was confused until he got home and saw himself in the mirror. Then he laughed. He had been that plumber. The one from the cartoons. The one from the jokes. He was, in that moment, a cultural archetype. He tightened his belt the next day. But not too tight. A plumber needs to bend.

Internet Angle

On the internet, “butt crack” is a versatile term that appears in multiple contexts. In comedy and meme culture, images of accidental butt crack exposure are a staple of “people of Walmart” photo compilations, fail blogs, and humor subreddits. The term “plumber’s crack” is used constantly in comments and captions, often accompanied by the emoji combination 🔧🍑. On Twitter, people share photos of their own or others’ accidental butt cracks with self-deprecating humor. The phrase also appears in fashion discourse, where critics and nostalgists debate the low-rise jeans trend of the Y2K era—some celebrating its return, others mourning the inevitable butt crack exposure that accompanied it. On TikTok, the “plumber’s crack” is a recurring visual gag in skits and pranks, often exaggerated for comic effect. In body-positive and fat-acceptance communities, discussions about butt crack exposure sometimes intersect with conversations about clothing design, fit, and the failure of fashion to accommodate diverse bodies. The term also appears in gaming and streaming, where “butt crack” is sometimes used as playful insult or banter. In medical and anatomical contexts, the intergluteal cleft is discussed in articles about hygiene, skin conditions, and surgical procedures, but these discussions are entirely separate from the slang usage. On YouTube, compilation videos of “funniest butt cracks” and “plumber’s crack moments” collect clips from TV, film, and real life.

Related Terms

Plumber’s crack — The most common euphemism for accidental butt crack exposure; associated with manual laborers bending over
Builder’s bum — The British equivalent of plumber’s crack
Plumber’s smile — A related humorous euphemism; the visible cleft when someone is bent over facing away
Low-rise jeans — The fashion trend that made deliberate butt crack exposure a style statement in the 1990s and 2000s
Plumber — The profession whose stereotype made butt crack exposure iconic
Mooning — The intentional exposure of the buttocks; the deliberate counterpart to accidental butt crack exposure
Wardrobe malfunction — The broader category of accidental clothing failures
Intergluteal cleft — The clinical, anatomical term for the butt crack