I think that there is a whole spectrum of nipple play. I myself do not understand what the definition is being used here. I know of plenty of people who the mere light rubbing of their nipples makes their cock rise and rise. Or is the definition something where one person takes something and clamps the nipples. So there may be lots of buddies that actually are into "mutual tit play", it is just the degree that they take it.
I definitely agree that a nice watch on a nice forearm is really sexy and nice to look at. However I would just rather look at a bare cock (or one with a bouncing hand or in me) than one with multiple watches on it. To each his own.