Among the Yanomami, who were discovered by the Spaniards in the Amazon jungle around 1630, a simple loin cord without an apron suffices as clothing. However, the penis is tied up to the loin cord with a loop around the foreskin. Only in this state, men feel correctly “dressed“ – otherwise they feel deeply ashamed, when they are seen with their penis hanging freely.

Yanomami men. Source: Usenet