Neon Nights (1981)

Sandy often fantasizes about her mothers’ boyfriend Robert. She pleasures herself while she watches them make love. One evening Robert sees Sandy watching as they make love and the next day while she is in the bathroom he invites himself in. Things start to get hot and heavy when Sandy’s mother catches the two of them about to have sex. Ashamed Sandy runs away from home. She hitches a ride to New York where her sister Denise lives.