It takes time to earn students' trust, which comes when they perceive no contradiction between your expressed policies and your reactions to what they do. Mandatory discussion is really pretty autocratic. Teachers who explain the rationale of an activity beforehand and model behavior before asking it of students will get less resistance. During discussion, it is wise to have students pause to reflect on the discussion so far, to jot down what is more troubling or more important. In particular, it's important to give students who haven't spoken the opportunity to speak, if they wish.
Groups post their views on large pieces of newsprint that are hung around the classroom.
Individuals move from paper to paper to write in their comments. Let students have the last word in a class, perhaps with a summary or a general impression. Much of the discussion centered on doing the job, being a colleague, and such. Such an assumption can get you to work three jobs in the time of one. A sort of self-crucifixion can result when we are called upon to lead one more committee or take just a few more students or one more section, even for more pay.