player in my home game thinks he's daniel negreuna and spends an aaaaaage over supposedly looking into peoples souls. Which is fine. But now he has this new trick that Im not sure is legal or not

Faced with an all in bet, after his usual questioning/delaying techniques....he then exposes both his hole cards looking for further reaction from his opponent before making a final decision

he does it every time. Is this legal? Its just that Ive never seen it done on ESPN :P