Another way to try..... do it first with a really light bow to get the feel, is to draw the bow as normal, but bring the arrow hand across the top of your chest, between the chest and chin. This keeps your elbow a bit lower and engages the back For ME, it is the best way to fully engage and use my back naturally. This allows ME a smoother release with my arrow hand going straight back.
I keep saying ME because it may or may not work well for YOU, since you are not ME !
This works very well anywhere, including in a tree.
Other than that, whatever works best for you is the best way for you. ( I think......)