According to the shastras, one should wear a cloth while bathing/showering.
This is one reason why Krishna stole the gopis' clothes.
But if you're wearing underwear while showering, how are you supposed to wash the genitals and anus? Are you supposed to pull down the underwear and wash the genitals and anus? But doesn't doing so go against the reason for wearing underwear, which is that not wearing is offensive to Varuna?
Or do Hindus simply not wash them and have stinky and dirty genitals and anus?