How do I play a guangdong/traditional style gaohu?

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I recently bought a mega cheap gaohu at a thrift store and set it all up nicely... and it sounds amazin
it’s one of those very old ones with a circular soundbox with a striped pattern, no base, and a dragon head. The snakeskin surprisingly doesn’t sag that much, but it’s very thin with small scales. Anyways...

How do I play this kind of gaohu between by legs/knees?
Where in between my legs should I play it?
How do I avoid having the bow rub against my legs?
What kind of cloth do I need to put below the gaohu?
Why is this playing position so painful for my back? lol

Thanks