kept playing and i think i answered my own question.
around 2/3 of the game there's a branching point where you can keep going the "lawful" path or believe the bad guy to join his side and get slowly brainwashed to follow their orders. for both paths there's a separate ending to the game, both of which are anal buttsluts endings.
here's savefiles for the last encounter in the game to see the scenes. save 8 is the lawful path and save 10 is the brainwashed path. just hold CTRL and choose "auto win" the fight to see the scenes.
as for the game itself, it's a good game. most of the content is in the towns talking to people with the heart to check out short scenes. most are relatively unique, despite how many scenes there are. some of them even default to anal (not because it's an anal scene, but the game detects she's a buttslut virgin).
if you want to see all these scenes, they're only in the towns (if there's monsters around, that's not a town). there's unique scenes during day vs night (you can pass time from the phone item) and also unique scenes for each MC (you can swap them anywhere with Q).
walking nude is finally unlocked around 1/2 of the game after you do a side quest to perform in a strip club's dance pole. you do the quest individually for each MC, but the quest unlocks for both at the same time.
unfortunately the actual battles are terrible. right after the karma branching point you finally unlock lewd skills in battle, but they literally don't do anything other than visuals. it's not like Karryn's Prison where you can win the game with sex.
my advice is playing on easy mode and never interacting with random enemies while auto winning every boss (all bosses i tested losing against took their virginities).
as an anal connoisseur, i'd rate the game 7.5/10.
as usual, JRPG RPGM game where battles exist for literally no reason whatsoever and you have to walk through a bunch of dungeons to progress the story. at least in this game you can avoid all combat, but you still need to walk around a ton.