Besides, bending it down is unnatural. If you have an erection when it is bent down the penis is not free to move. The blood is flowing inside and the tissues are not free to expand. When it's up, the penis is held against the abdomen, not folded in half, and can expand as needs fit.
I don't find an erection in the up position is very noticable in class; but, when it's in the down position, it makes the look awkward, and is certainly more apparent.
That's my opinion.
balletboy[/i]