1. "Concealing shame" is regarded as the main function of underwear by many men. 2, protect the testicles, because the testicles need to be two degrees lower than the normal temperature of the body, which is its best temperature. Pants can insulate some heat from thighs and abdomen. 3. It can also reduce the friction between thighs and outer pants. 4. Prevent bacteria from polluting pants after residual urine or feces. 5, evenly prevent odor leakage.