Better to wash hair upside down or standing up?
What gives better curl definition?
I guess it all depends on how your hair behaves. Try both and see for yourself. I know for me, it doesn't necessarily give me more definition when I wash my hair upside down, but it tends to give me more volume (which I love). If you do want more definition, try twisting and scrunching your curls when applying product, and blow dry your hair upside down.
I find that washing and styling with your head up gives more definition, whereas doing it upside down gives more volume. More volume does tend to give less definition though. Personally, I wash and style right side up, and then flip my head over and continue scrunching in product.