Well I took Tracy's advice with my second born (sprited touchy) and the stubborn little thing refused to ever latch on again. So BE gentle.
With this one #3 I have just said ouch! That hurts mommy and then taken him off and patted his back for a couple minutes before letting him back on. One time he really nailed me and I cried out in pain (pure shock, didn't mean too) and I scared the ens out of him. He started crying and at first woudn't latch on but after my experience with number two I knew to gently encourage him to latch back on, and he did. He has nibbled a couple times since but hasn't hit me hard again (yet). We're in the same boat, first two came really quickly and the top ones are working their way down now.
IMHO a wet washcloth (or better yet a washcloth one end dampened and partial frozen) is the best teether. Try letting him chew on something before he chews on you.
LOL!
Good luck!
