Our 2 cats like to spin the roll and play with the TP as it piles up. If you reverse the roll though, they can spin to their hearts content without actually creating a pile of unrolled paper (although, you have to discard some due to their claws perforating a couple of layers!).
i totally disagree with the "over" technique. i don't have any cats but i still far prefer the "under" style! maybe it's because i'm a lefty--i'm sure i'm not alone...