I was thinking of a way to make music while on holiday as there was no space in the car for the guitar 🙂
Looking around at home unearthed an old harmonica which fitted the bill perfectly. It can be slipped into a pocket and played anywhere. My harp chops were a little rusty but it is coming back.
I have read that after 10 hours of harp playing you will have learned all of the required techniques and all that is required after that is learning songs. I think that this is true as I find I can still do the note bending etc. but need to remember, look up or work out some songs to play.