I just did Crab for the first time the other day. Talk about an
awesome view!! AND a great ab workout for both parties involved.
It's very akward and uncomfortable on a bed which is why I've never done it (or forgot because it was quickly abandoned).
But when one person is on a couch and the other lover is on an opposing chair. It's pretty friggin AWESOME!!! Also toward the end, she ab-curled up over onto my side and turned it into CG finish. Very nice!