Scrivendo dei rituali di iniziazione sessuale delle tribł della Nuova Guinea:

At around age seven, boys in some highland tribes moved into special domed huts, where they spent their days and nights servicing older adolescents and occasionally grown men. “You should not be afraid of eating penises,” the elders instructed them: they believed that semen strengthened young boys the way breast milk strengthened infants. Oral and anal sex also allowed the boys to “store up” semen, since some tribes believed that men didn’t produce semen naturally.