Scene has Mick Blue as a pervert of an anatomy professor, browbeating student Adriana Chechik into submitting to his will in terms of anal probing. Yes, gaping is the fetish he's studying, and adding to the vignette's naughtiness (i.e., sleaziness, pandering to the fans' baser instincts) is the central premise that he abused her sister previously.
Lest this be called all-anal, Chechik also gets to show her deep-throating skills.
So we get to see Chechik's well-known gonzo abilities on display in clinical fashion -arguing for the importance of gross-out over eroticism on the current scene. She's a capable actress and seeing her abused is hardly my idea of entertainment.