Alright, I watched a movie back in the late 90’s or early 2000’s on cinamax (in English and color) about this group of people who attend this dream clinic and the woman that ran it, or just worked there (I’m not sure which) would trick the people once they were asleep into having sex with her and that would trap them in the dream world where she would then kill them.
http://www.imdb.com/title/tt0116142/?ref_=nm_flmg_act_23