Legend of Siren : Erotic Ghost (2004) aka Shin yôjo densetsu: seirên

After successfully robbing a bank, five men kidnap a beautiful woman that happens along their path and take her to their hideout as part of their “celebration”. But the woman is actually a supernatural creature that can kill with her voice, and she uses her beautiful exterior to alienate the greedy men and turn them against each other to bring about their deaths.

Kapop (2003)

This Thai flick is pretty funky in its' production values and acting level - plays kind of like a high-school made video. The 'plot' involves the 'ghost' of a girl who was saved from a rape by a witch/ghost who then inhabits her body and wreaks vengeance on a series of unsuspecting guys by murdering them during sex (chomping off their privates!). A group of students makes a field-trip to the village where this mysterious carnage is occurring and gets sucked into the 'horror' and sex!