Two Girls for a Madman (1968)

Dance students Toni (Arlene Farber) and Sonya (Jean Weston) become 'Two Girls for a Madman' when toothy psycho Frank Yeager (Lucky Kargo) sees sexpot Toni at a bizarre back-room orgy in Greenwich Village. Impressed, Frank pops up in the back of Toni's car and "teaches her some new ballet steps". Wanting seconds, Frank starts stalking Toni, quickly discovers her best friend Sonya, and ends up breaking into their dance school, anxious for a private performance...