Ok...ugh, this game is so frustrating...but I think I've figured out the sequences to unlock all the ilogical content progression.
The trick is that pretty much 90% of the non-battle rape content is sidetracked into optional totally missable areas and that you have to do them in order, so it never unlocks by the lewd stat alone which can be hella deceiving and counterintuitive.
Ok, where things first get hairy (at least for me) is around the sea guardian/underwater cave. You have to find duke and his men there, which is a very waysided optional area, so you can trigger mai's debt progression... There, I dunno how much time I wasted because of such a badly designed and loose progress condition. But ok, at that time I took it as a personal challenge out of spite.
That triggered, you can now progress with the panty > delivery > brothel sequence. Also, somewhere in the middle you need to trigger the youth member by the castle and aina In an alley at north part of town during night, also trigger mai's bear and invite to sex from edgy guy. Then you'll eventually feel lost because there's nothing else you can do in town that doesn't say you need to do more stuff before doing that.
Right, so here's the second important bit of information: remember when the game says you could now explore scenes at night? Remember how you couldn't leave town? Yeah..... That actually means you can now leave town and roam vast stretches of land during the night chasing dick.
During night now you can go to the mountains east of town and you can trigger a scene by the road. Do that once or twice again, then you can go to a new area that only opens at night, a remote house with a demon you can now fight and unlock a new scene by the house. Now you can finally unlock strip and banquet and unlock night scene at the castle. Not sure this is the exact order, but it's one or the other.
From there on you can figure out how to unlock the rest of the stuff, like talking to aina and helping out the bandit leader, the hotsprings at night, etc.
(angry sweaty twitchy eye noises)
...
Anyway, hope this can help some lost souls