That prettymuch says it all. Is there a position that is significantly “better” than others? I’ll leave the details up to you to help define “best.”
According to the book “How to Shit in the Woods” by Kathleen Meyer, squatting slightly lower than a sitting position is the best position.
No, I didn’t make up that book title.
Hard to beat the regular squat on the toilet. it is ergonomic and gravity is on your side.
Real men crap standing up.
I have to admit, I would love to travel in the orient and areas of the mideast, but with my knees I know absolutely i cannot use a squat toilet…I can stand or I can sit, my knees do not have a middle hold point, or one that i can get down into and up from without a crane or 2 helpful people [I know this because of getting an award in the SCA and having to kneel. I simply cant just ‘get up’ it take significant work=\]
So, what do the natives do when they have knee and hip problems? What would I have to do to manage…take one of those little folding camp stools and make it have a hole in the cover to go through? 
My uncle had a dog that would shit while walking. The dog was just walking along, with a turd popping out every few seconds.
Squatting. You rest on your thighs/haunches. You need Mediterranean, Middle Eastern or Asian ‘hole in the ground’ toilets (or the woods). Trust me - it just plops out with no effort required. (A veg- and fruit-heavy diet helps, but all else being equal, squatting is still the way to ‘go’.)
Post-bowel movement cleansing is also very effective this way. You wash your hind quarters witjh water (from a bucket or hose), using the fingers of your left hand (traditionally). Obviously, a good scrubbing of the fingers with soap is in order afterwards. I still do this today at home in the shower when I’m in my pyjamas or some other easy-to-pull-down clothing, despite having a Western-style sit-down toilet. Toilet paper is a pain.
Enough information?
You poop in the shower wearing your pajamas? :eek: