Girl slip with secret stash S-LOn the inside of the underwear, in the genital area, is a small pocket that is best used to heat and maintain the temperature of our synthetic urine, CleanUrin. This is the only part of the body that cannot be searched during checks. Even robbers won't look here for valuables. Credit cards, money and other valuables can be stored here safely. This makes the underwear perfect for travellers too.