Wearing underwear as outerwear is a fashion trend popularized by celebrities, sports and media. It began as a practical and comfortable variation of clothing, such as the T-shirt and the sleeveless shirt, but later evolved into provocative, controversial fashion statements. 21st century versions include the display of thongs and bras in women's clothing, and the display of underpants under low-slung pants in men. Wearing underwear as outerwear has historical antecedents in the display of undergarments in the sixteenth and seventeenth centuries.

Indecent exposure is the deliberate public exposure by a person of a portion of their body in a manner contrary to local standards of appropriate behavior. Laws and social attitudes regarding indecent exposure vary significantly in different countries. It ranges from outright prohibition of the exposure of any body parts other than the hands or face to prohibition of exposure of certain body parts, such as the genital area, buttocks or breasts.