its definitely legal and does not fall under the jarring rule, that is 99% defense or lose ball when both players are digging for the ball...in this case, he technically has possession of the ball...now, that said, it he was doing that on any table I was playing on, I would stop him because it is a great way to break men, its very abusive to the table. Spinning is also since there is so much power generated (usually) and the man often comes down super hard right on top of the ball...breaking roll pins, men, and/or potential damage to surface....last about the squeeze shot, as the person before said, its not a good strategy because he is not controlling the ball and can plan where it might go...it generates power and crazy movement and for a beginner, it feels powerful and is fun to make the ball fly around uncontrollably hard and fast....to be blunt, it is dumb and destructive and doesn't achieve making the person look cool (which is their motivation) it makes them look like a hack to anyone who knows anything about the game...its in the same category as spinning as far as being bush league