This Shock Doctor Titan was the perfect item for self defense classes.  Like any cup, it restricts movement by a small amount, but the dual-layer gel lining offers the most comfort I have felt on a marble guard.  It is also the most attractive cup I have seen, which is kind of a secret bonus because it will be out of sight when in use.

It is called a "flex" cup, and it does to a small degree.  There is a 10-15% change in shape when body pressure is applied before it really pushes back on the skin.  As long as I don't have to sit down for extended periods, it never gets uncomfortable.  I only bought this item because I saw a truck run over one on Youtube and the tomato underneath was unscathed.

I never paid more than $10 for a cup before, but I like tough hardware and this was a good buy.  My man parts are confident and ready for kicking when I put this on.  5 stars for a next-gen design, extreme comfort, and sturdy construction.