for me, that would raise concerns. i don't want to have sex with a 'filthy bastard'. if i had to call him that i'd think he wasn't for me. that doesn't mean the sex would be limited in scope - just that the language would be more positive.
Ah, now you see, for me, filthy bastard is wonderful (and I don't HAVE to call him that, I call him that because I want to and we both like it). So is soft and romantic or naughty and quick or slow and seductive. Depends on our mood. The point is, we discuss it in advance so it is always consensual.
If YOU wouldn't like it, then it is wrong for you. But WE do like it, so it is right for us.
Slut has unlimited negative connotations .... It's deliberately demeaning
But it does depend on the person and the situation. I love filthy, uninhibited sex. I love being demanding. That is what we describe as sluttish behaviour. There's nothing demeaning at all when he uses the term on me, when it is my intention to be slutty with him (willing, sexual, filthy wife) But that is entirely between the two of us. I wouldn't want him to call me a cunt because it's not a word I like, so he would never use that. He would never call me a slut in any other context and there is no demeaning in our relationship at all. He is an incredibly considerate and loving husband.
Both people, when having a sexual relationship, need to be able to communicate their likes, dislikes and desires to each other, openly and honestly.
If one person wants to try something, they need to ask.
If one person doesn't like something, they need to say so.