Some one explain it to me, what was this all about? Who is who? who did who?

It's porno, dude. Don't think, just fap.

as far as I can tell, it's about a schoolgirl shrine maiden who ends up living in a huge mansion people, and she has awkward but passionate sex with most of them, then gets spanked, and there's a dead [???] woman in a yukata who needs the young couple to wear Seran-wrap [making them ultra-horny for some reason], then making them fuck on a wooden contraption inside a mountain, resulting in an earthquake from the dragon-sized kamehameha-wave penis

then it's over

Keep in mind I haven't watched this completely in order, for obvious reasons. I never really do that with hentai.

It has lesbians.