Firstly this is not a slasher movie nor could it even loosely be described as a horror it can barely even be described as a thriller as it's largely quite boring, the sex is not explicit and the violence not extreme.
I personally didn't feel the film was misogynistic and was one area where the film did succeed by not overtly portraying the females as victims except in places to (unsuccessfully) elicit sympathy and create tension. The female characters are simply one of two opposing sides that develop as a result of the titular sexual act which accidentally results in death which is an alternative to traditional good and bad set ups (as seen in say Eden Lake). If this element had been developed and handled properly it could have lead to an interesting moral conflict instead of lazily resorting to the thriller default plot devices of anger, fear and friends turning on each other.
In addition to the script problems some judicious editing to reduce the running time to around eighty minutes (from 95) would massively help the films leaden pacing which contributes to and ultimately cripples what could have been an interesting and original drama/thriller.
