In a word (or four) PLEASE DON’T DO IT! Fortunately, I have only seen a couple of these in "real life". I have read of numerous cases in our dental journals which have resulted in all sorts of problems. To begin with, the tongue is an extremely vascular organ, which means that it has loads of blood vessels. A tremendous amount of swelling is expected when the tongue is pierced and a large oversized "barbell" is initially placed to accommodate for the expected swelling. This can cause difficulty in breathing and swallowing. Eating, drinking and speech are all impaired. The large barbell flops around and has caused un-restorable fractures of teeth when accidentally bitten. The barbell can come unscrewed and be swallowed or possibly be aspirated, sucked into the lung. Either of these could require surgery. I repeat, PLEASE DON'T DO IT!