The main thing is this. I need something to inhibit me from constantly jumping in with either i) interrupting reassurance or ii) some interesting, pedagogically valuable, comment (of which many come to mind). So I’ve engineered some sort of gestalt switch in my head. When a student says something, instead of thinking that I am depriving her by not responding (either assuringly or interestingly) I think to myself that I am depriving her precisely by responding – depriving her of the interaction with her peers, the reasons they can give to her, and the opportunity to surprise them. If the conversation ebbs, or if some particular strand is, in my opinion, played out, I step in an prompt the discussion with further questions, and often with low-pressure cold-calling (I also deploy gentle cold calling as the discussion moves along – if someone hasn’t spoken yet, or recently, they obviously go to the top of the queue, but also if someone looks like they are thinking, and haven’t yet spoken, I’ll call on them to see if they have something to say). My rule of thumb is that on average at least 4 people should speak in between every time I say something substantive (as opposed to just calling on another student), and as long as I keep to that, discussion goes well.“Making a classroom discussion an actual discussion” at Crooked Timber

Good advice from the folks at Crooked Timber (an academic blog very much worth reading), but I would find this advice hard to put into practice for the reasons suggested above. The whole post is worth your time, especially as we move into the new fall term.