First off the modern "Birds and the Bees" discussion acts like sex is a taboo subject, as does our modern society as a whole. However in places like Ancient Greece we can see that was not so true. In places like America, in places like the US you can't show sex (actual not fade to black) or genitalia without being on HBO or other private channels you have to purchase, however on Anceint Greece statutes were routinely shown naked, the Romans even had a winged fascinus, which was a penis amulet worn to ward off envy, (see images here ) opened about sexuality varies from culture to culture still. You can tell a lot about a culture from their art and Mythology/Religion, and I encourage you to investigate that for any specific culture I didn't mention. How the conversation probably went was a matter of how open the culture was about sex. A Roman one was probably very straight forward while, 11th century peasant boys "talk" resembled today's with its idea of sex as "taboo" .