All I can think of is possibly redirecting his attention...when you suspect he's about to bite or pinch, try to divert his attention elsewhere. My son has been a big thrower since he was about a year old. Sometimes he directs at others, sometimes he just throws in whatever direction feels good in the moment. It's never malicious, though, just like your son...he just does it to get attention or just to have fun. We'd either ignore the behavior or if he was putting others in danger then we'd try to get him interested in a toy or game. Most of the time it works, sometimes we have to simply remove him from the situation. There really is no simple solution, unfortunately...you've just gotta figure out what works for him and flow with it. Another idea is to hold his hands together when he's trying to pinch or putting your hand over his mouth when he's going in for a bite...a version of nonviolent resistanceThat'll let him know in a nonviolent, pro-active way that it's not okay to do those things...it'll probably frustrate him at first, but once he gets the message he'll learn to express himself in different ways.