Murderous Maids meets Monster, Giada Colagrande’s debut feature is a grim, risible downward spiral of pseudo-porn. Maria (Natalie Cristiani) hooks at home, where she essentially imprisons her 17-year-old sister Caterina (Colagrande). Big sis provides prostie homeschooling, teaching her sibling Dante, Donne, and Galileo by day and cunnilingus as a second language at night. The pallid pupil (who bears an uncanny resemblance to Mia Kirshner, in both her Exotica and L Word incarnations) can break house arrest only to attend dance class, where she meets middle-aged horndog Giovanni (Claudio Botosso), who’s soon giving the tiny dancer lessons in doing it doggy-style. Wrathful Maria poisons her rival and pimps out her AC/DC charge.

How do you solve a problem like Maria? Open My Heart is cluttered with several inelegant cuts to paintings of the Madonna—which only underscores the redundancy that the elder sib is both the mother and the whore. Colagrande’s lezzie sorelle exhibit none of the ferocious lunacy that marked the incestuous bond between the Papin sisters in Murderous Maids. Those looking for a smarter précis on sex and shame with one-thirtieth the running time are encouraged to seek out the other Madonna’s “Open Your Heart” video on VH1.