i have 24 cards with all major and minor chords written on it (survival supply, just like dental hygene products and chocolate and a towel of course)
pull a tune, for example: three cards for the chorus two for the bridge.
beaware of morphic fields, places mostly home to guitar players tend to produce tunes centered around E,
for example i got : F#minor B C#minor E Eb
recent experience showed the danger that the improvisation degrades to something like a jam in a-minor or similar, be warned and prepared. possible preparations
- alert everyone, twice at least
- uses cues and breaks
- set up a bigger structure, by dynamics, tempo or enlongated harmonic rhythm