Bachelor Party in the Bungalow of the Damned.

The story focuses on a group of thirtysomething guys who head up to the Hamptons to a buddy's bungalow to throw a bachelor party for another friend. Once there, a group of middle-aged, overweight hookers (who look nothing, NOTHING like the girl on the cover. . . not even a little bit!) stop by randomly and give the boys a show. Unfortunately, they're possessed by some type of evil/demonic force and they started to kill the guys off (mostly during sex) one by one.