Girl in stockings on the stairs masturbates her hairy pussy first through her panties, then takes off her white panties and fucks her wet hole with a dildo. Then the girl inserts a sex toy in her pussy and in her anus, fucks both holes, does double penetration.
It's gross, but I think every third person fantasizes about it.
If I were my professors, I would recruit more of these beautiful, and most importantly, stupid students to study. The test in the classroom was very effective.