Slumber Party Massacre II (movie, 1987)

Courtney, the sister of a survivor from the 1st movie and the members of her rock band go to a condo for the weekend to play music and have fun with their boyfriends. Courtney's dreams are of her sister, who is in a mental institution, warning her of having sex, and the dreams begin to spill into real life, threatening Courtney and her friends as they begin experiencing an attrition problem.