Step one: Pick a jam where you can choose an appropriate response.
Step two: Don't do anything that makes folks complain.
I mean sometimes in a larger jam if there is a tune that I'm trying to get into my head, some quiet noodling is important. Trying to find the melody notes, the right chords, etc. Just takes discresion (sp). If I know the tune I'll just start to play notes, chords etc. Mostly I play in unison with old time folks. Sometimes the lead will go around the circle - again, it just depends. I still try to keep my antenna up to make sure that I'm not too loud, or otherwise dominating/annoying.
ˇpapá gordo ain’t no madre flaca!
'20 A3, '84 1N, '84 A5-1, '06 Phoenix Bluegrass, 2012 Cohen A5, 2012 Muth A5