Usually I come in with topics I'd like to discuss and direct the discussion. And sometimes my t will take the discussion in an unexpected direction, and I have found the feedback or discussion valuable in retrospect, partly because it is a perspective or insight or direction I hadn't considered.

But it is difficult to focus on topic B if you're trying to discuss A. Maybe there could be some value to asking the t to follow your lead, but set aside the last half/x # minutes of the session to discuss the topic they've got in mind?