I've shot 3 deer hunting from natural ground blinds that consisted of nothing more than a small folding chair and some brush thrown around it.

I forgot my chair one time and hunting while sitting with my bum on the ground just wasn't going to work- I was way to figity and uncomfortable.

I dug in once making the ground low enough to allow my rump to sit on mother earth while my legs & feet were subterrainian. It was OK this way, but I didn't see anything.