I was going to suggest you might try the classical type of device, as used by Willie Nelson and Segovia. Dunnio if it's work with a banjo, because the centre of gravity is at a different place. Putting your leg up on a chair might be the right way for you. Depends what you're wearing...

soccer ("football" east of the Atlantic). Also South of the Rio Grande, West of the Pacific... - in fact just about anywhere outside the USA (and I suppose Canada).