Never never mind off-thread posts - make them often enough myself so can't really complain!
DS bit me several times when he was teething. I tried:
pulling him in to my boob to block his nose and make him more likely to let go to breathe through his mouth - so the theory went... He clung on with the couple of teeth he had, growled and bit harder - it was like feeding an angry puppy!
rubbing teething gel on his gums to make him less likely to want to bite for comfort, with limited success.
giving him something cold to chew on before a feed, he hated that.
feeding him with one hand millimetres away from his chin and watching him closely. As soon as I saw his mouth shape change in an "I'm just about to bite you" fashion, I grabbed hold of his chin, pulled it down, pushed him away from my boob, tapped him gently on the nose and said, "No!". This last one was the one that worked for me, but the others might work for you. The other thing to do is to put him down and refuse to feed him, although if you're predominantly feeding him at night, this might not be the way forward...
Never smile, even if he grins at you. But I'm sure you don't, as it's not bloody funny to be bitten on the nipple! Good luck with it - I found it lasted a couple of days, but was soon over. The anticipation's the worst bit though...