Can be played with endless fluster! (6)
I believe the answer is:
flutes
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for flutes that I've seen before include "Pipe-like musical instruments" , "High-pitched woodwind instruments" , "Wind instruments as played by James Galway" , "Musical instruments as for James Galway" .)