Cinemachine: The Howling II: Your Sister Is a Werewolf (1985, Phillippe Mora)
The Howling Collection — The Movie Database (TMDB)
The Queen of B
Apparently she is trying to cast a spell upon Stefan.
That film was directed by Oliver Stone, who went on to cast McEnroe in very small roles in many of his later films, perhaps viewing her as a good luck charm of sorts.