A Zwanenfucking is a case in which a student's schedule is mangled, often irreversibly, by an incompetent school counsellor. Can also refer to said particularly careless counsellor.
John: Hello Mindy, why the long face?
Mindy: My counsellor signed me up for a class I passed last year, and wood shop in the timeslot I wanted photography! Now the classes are full and I can't switch out!
John: Wow, you just got royally zwanenfucked!
Carson: That Mr. Johnson is such a zwanenfucker!
Lyle: Good thing we're graduating, I've had to deal with non-stop zwanenfuckage for three years!