Tucking refers to the practice of hiding the penis and testicles so that they are not visible through tight clothing. The most effective way of tucking involves pushing of the testicles up into the inguinal canal; most can do this without any pain. Once this is done the penis is pulled back between the person's legs and a tight pair of panties or a gaff is then worn over the top to hold everything in place. Trans women particularly resort to tucking when wearing more revealing clothing such as leggings or swimwear, as for trans women who have not or do not undergo genital reconstruction surgery, the penile crotch protrusion (sometimes known by the slang terms "moose-knuckle" or "man-bulge") can be among the most conspicuous signs of the gender they were assigned at birth.