Little bit of both. You gotta find that sweet balance spot

I find that keeping your shoulders parallel to the nose and tail of the board helps

Forward is easyst

Nope

It all depends on the rail itself. If it is sticky, you’ll need to lean backward to slide. If it is slick, you need to lean a bit forward if you don’t want to slip out. The best way is getting it slick so you don’t have to put more effort on sliding the rail and leaning forward is always safer than leaning backward.

Yes