I don't think your twisted. I mean you said the girls are fine with it & gets turned on by it, so there's nothing wrong. . You also said that you only want them 2 feel like that during sex so hey, whatever works for you & her ; )
That's not weird. A lot of women have a desire be dirty and slutty in bed, but are not comfortable truly expressing themselves, because they don't want to appear too slutty. That is one of the reasons a lot of women want to feel dominated in bed. It takes some of the responsibility away from them.
No, not weird at all. In fact I feel similar to how you do. I have different fantasies and whatnot, so I like this one day and that another. But yeah, seeing a girl really get down and enjoy sex, doing dirty things, etc. is really hot to me too. I doubt that it's rare either, so you aren't weird for liking it.