Both are rather tasty, I have to admit.
The headmaster having you under his desk,servicing his cock and balls while having other parents in for conferences regarding their kids. You have to keep your mouth busy on him, but can't have him cum otherwise your shame will become public.
The P.E. teacher having you come in after practice is over - sharing you with the assistant coaches, and then the other female P.E. teachers.
Oooh I love the way your mind works