nsfw Where do our ideas about what sex is come from?

In a question about how people think about what ‘sleeping with’ means, people had a broad range of ideas of what should be included. Some were pretty straight forward and limited (vaginal penetration and orgasm) and others included an awful lot more behaviors.

What I was wondering is where we get these ideas. I’m not just talking about religion, but more about culture and parenting and schooling. Why do some people make it so specific and others include far more?

What influenced your ideas about what sex is? Have those ideas changed over your life? If so, why?