I think all of us tend to forget that Jily happened back in the 1970s, and not in the 2000s.
And that’s why James or Sirius or anyone of them sleeping with each other before graduation (or if you’re being radical - seventh year), is highly impossible.
It doesn’t matter that they lived in the wizarding world, sleeping with people just wasn’t really accepted at that age, in those times.
Uh, I think you need to research the 70s more because casual teenage sex was definitely common.
if it was the 50s, then you have a point
but the 70s, really?
you guys know that when people say 70s they think about sex and drugs
Not to mention teenagers slept together in the 50s. And the 40s. And the 30s. And on and on and on.