It was only a joke, not a jugement... It's just that there are so many pigeons flapping around at once !
Clay-pigeon shooting

But, maybe try to make the drone continue as you're squeaking through the nose.
It's easier with puffed-out cheeks.
But once you get it, it can be achieved with flat cheeks.
Edit : I remark that all of us Balandas (Guan, Martin, Paul and I) are making a "Hmm" while Datjirri is making a clear "Hee".
I just can't see how that's possible ! It really sounds like a mouth noise ! Amazing !
I'm trying to get that "Hee" alone without the didj but it seems impossible.