The Exhibitionist Files (2002)

Lisa (Catalina Larranaga) is a beautiful sex researcher on a serious assignment: She's trying to discover why exhibitionists enjoy having their naked bodies seen by those who are not expecting to see them. She learns that office interviews are not enough and so she arranges to watch those being watched, to make notes as to what turns them on, and how. Soon, however, she tries it herself, by having sex near a window where she can be seen by an entire apartment building. What she learns is that she's a closet exhibitionist and likes it.