Omorashi (おもらし / オモラシ / お漏らし?), sometimes abbreviated as simply "omo", is a fetish subculture recognized predominantly in Japan, in which participants experience arousal from having a full bladder and/or wetting themselves, or from seeing someone else experiencing a full bladder and/or wetting themselves. Outside Japan, it is not usually distinguished from urolagnia (urine fetish), though they are different things. Westerners who do make the distinction commonly use phrases such as "bladder desperation" or "panty wetting." The Japanese language term from which the subculture's name is derived means "to wet oneself," literally translated, "leaking." The word is also occasionally romanized as "omorasi" in the Kunrei-shiki romanization system.
Most fetish activities concerning the use of bodily waste are considered by the general public as "hardcore", taboo, or edgeplay. However, because the object of the fetish is clothed incontinence, omorashi videos do not necessarily feature direct sexual contact. The focus on clothed (rather than overtly sexual images) makes garment fetishism a prominent feature in most omorashi erotica: commonly featured outfits include those worn by schoolgirls, working professionals, and other people attempting to look dignified before succumbing to the need to urinate.