Yeah, like I said prior I'd be fine if it was JUST Carol or if your anal preference response actually affected the future toy scenes, but it doesn't appear to. And now you have Ashley as well.... it's pretty clear this is a pet fetish of dev that's spilling over into way more scenes than would be expected. In the real world world some girls are definitely into anal, but others have zero interest in anal sex or buttplugs and all that stuff.
I feel like the writer isn't sure what they want to do with Nikki, on one hand she's the "cool girl", the "one of the guys girl", and those types are usually very nonchalant about sex. On the other hand, he's creating this slow progression with her, I think this leads to the juxtaposition.
Her dialogue is well done for the character, very laid back when it comes to sex, but then the action never really happens..
Carol has a different issue, the game started with all these intertwined plot lines about her on the cheerleading team, and her involvement with the sorority which presumably pimps girls out. Somewhere along the way, all that stuff took a back burner to mc sleeping around with all the other girls, so what's left is Carol is just kinda "there", going through the motions of sex scenes but none of it really has any gravity for me at least.