On a open hole wood flute (but not a keyed one I suspect) if you finger G and then place one, two, or three fingers of your right hand down and then very rapidly slide all the right hand fingers up to open the holes then back down across the holes and clear of them again and repeat this sliding motion to a set beat you get an unusual (to me) effect.
With practice it could be useful I think.
Is this a well known technique I simply have not heard of?
Hmmmmmmm…works alright…might be annoying enough to get someone to start a tune ???
I vaguely recall reading about it on the whistle forum a couple of years ago I think. Someone had offered it as an ornament in place of double-tapping G.