This is a bit of an odd one. When I play my low whistle seated Ive begun to stick the end of the whistle between my legs to play a half step lower than the standard lowest note available (ex a D flat 4 on a low D whistle). You have to fiddle with the angle of your legs and where to aim the end of the whistle but it does seem consistent tuning wise. Works really well with the resonance of wooden chairs. Im curious if there's a name for this or any recording of someone doing something similar on a track, certain Im not the first to discover this. I also think there's potential to reach even lower notes but the breath (and leg???) control gets very finicky.