The life room was crowded, so I decided it would be more convenient to draw left handed rather than across my body. I've drawn left-handed for short poses, it's quite a common exercise, but never attempted a long drawing as far as I can remember.
I think one of the difficulties of drawing with the other hand is that all we change is our hands. Otherwise we stay in our habitual stance and shortly afterwards lose our balance. I find it helpful to find where my feet are, and switch the position around.
As I have written elsewhere Jimi Hendrix was an artist who was highly ambidextrous.