My NVC teacher is offering a free practice session on 26 March. It’s branded as an introduction, but the way I have experienced it, it can be insightful for people of any level. What you’ll get is a bit of theory, and then an exercise one-on-one, with the possibility of getting the assistance of a trainer-in-training. I can only recommend it.
More details and registration (free but mandatory): Free introduction to NVC - Connecting2Life - The Art of Dialogue