Killamajig: Sandpaper is downright pleasant by comparison to shark skin - it's actually composed of what are essentially tiny teeth. There's a pulpy cavity, an enamel outer coating, the whole deal. Rubbing a shark the wrong way can skin you. As long as you could tell which direction the scales run and pulled your hand away 'with the grain', so to speak, it'd be like slapping any other fish. 'Bleeding heavily' would only take one mistake, however.
Sort of want that Garchomp? mm?
Nevertheless, I would spank that delicious ass hard without a glove, until one of them is raw and pink, or the other bleeding heavily.