I have only shot on the right side, modeled after Ishi the best I can figure. Never learned on the left. Its a push pull combination for sure.
I come right off the bottom of my neck and push and draw at the same time. I always get full extension with my bow arm. You should develop a small turning away of the bow upon release (keep your bow hand loose, tight grip is no good). Look at all the photos of Ishi and you will get good clues as to how its done. I hold the arrow just as he did, and after I got it down it feels very comfortable. Its not a draw and hold type of shooting, quick release is how it was done. Sounds weird but imagine a trombone being played - very similar movements. You will first shoot way right. It will make you think you have to aim left... don't. Twist/lower the bow down to align the arrow with where you want it. It will feel weird, as if your drawing back at an angle, but your not. Anyhow thats how I practiced over and over to get it down. At 20 yards I can get a good bunching of arrow within a 8'' of each other. Never been taught. There is a good video online, by a fella who shoots a couple arrows in a backyard while crouched. I'll look for the link. I like Billy Bergers video as well, but he's a bit awkward with it. The other fella is smooth and natural with it.