Underwear fetishism is a sexual fetishism relating to undergarments, and refers to the sexual excitement which some people experience from observing or handling certain types of underwear, including panties, stockings, pantyhose, bras, or other items. Some people experience sexual excitement from wearing certain types of underwear. Other people experience sexual excitement when observing or handling certain types of underwear worn by another, or watching somebody putting underwear on, or taking it off. Some may steal used underwear to get satisfaction. Not only does this include physical contact with the garment(s), or their wearers, but also includes arousal by printed material or electronic material that includes depictions of underwear.
Underwear fetishism is not considered as paraphilia unless it causes distress or serious problems for the person or those associated with them.
Panty fetishism is a fetish in which one eroticizes panties (or similar styles of underwear).
Fetishistic behavior can involve sharing printed or electronic material depicting exposure of panties, usually of a softcore nature, or direct sight and physical contact with the panties.
Some individuals have a paraphilia for a specific type of panty. For example, a common subclass of panty fetishism are panties that show the exposed buttocks (i.e. thongs and g-strings). Further, some individuals have the opposite preference, and are attracted to panties that cover the buttocks.
One of the most common types of panty fetishes involves used panties. In this fetish, panties or other intimate clothing that have previously been worn are eroticized. With the advent of the Internet, a "used panty" industry has sprung up to cater to this fetish, consisting primarily of women selling their used undergarments through independent websites or panty seller groups. Sellers tend to charge for the number of days for which the panties or other garment are worn, and prices generally increase with time worn. In Japan, this industry has a long-established brick-and-mortar presence, known as burusera shops. Outside Japan, such shops exist only on the internet and are generally run by individual women, as opposed to registered businesses.
To determine relative prevalences of different fetishes, Italian researchers obtained an international sample of 5,000 individuals from 381 fetish-themed discussion groups. The relative prevalences were estimated based on (a) the number of groups devoted to a particular fetish, (b) the number of individuals participating in the groups and (c) the number of messages exchanged. Within the sample population (a population of adults online involved in sexual discussion), 12 percent indicated a fetish related to an "object associated with the body + external event" . This includes, but is not limited to, objects such as underwear, socks, shoes, etc. (see Table 1 in the .pdf of the first article cited).