I teach a graduate course on pedagogies of improvisation in music learning, and we had a visit from Akihiro Uchida, a master old-time fiddle player based in Japan and the US, and with whom I often played while living in Japan. We had a very informal and impromptu sharing session, mostly a jam with a bit of question and answer. If you’ve seen the above discussion of participatory music, you can see a bit more in-depth example based around one style of playing.