Cooperating teachers are charged with the task of taking a student teacher under their wing. They are expected to provide good ideas, sound advice, expertise and guidance.
A cooperating teacher should be supportive and positive, although the majority are jealous, lazy, bored or a combination of all three. While veteran teachers do receive a small sum of money for signing up, the student teacher actually pays for the privilege of becoming slave labor.
For ten to sixteen weeks, the student struggles with the work of two teachers while their so-called mentor takes long lunches, leaves early, and invents strange copy requests that take hours to complete. At the end of their tour of duty, the student teacher is rewarded with criticism and not-so-kind words from their host.
In other words, cooperating teachers are notorious for not being very cooperative.
See also: She's A Witch! Burn her! BURN HER!