渣女refers to those girls or women who are dating several men in the same time or dating someone and sleeping or flirting with someone else. It is more emphasis the moral or personaility. Girls who like to manipulate men and cheating on them. While slut is more about sex, there is a difference. I would say bitch.

sperm bucket

Bitch is all right.

Honestly, I don't see why you can't call a girl a douchebag

Culturally, it would be a "slut"/"floozy"/"tart"/"strumpet"/"whore"/"harlot"