I sympathise! DS2 is doing the whole biting thing at the moment. No teeth yet, but I still have cracked nipples as he clamps down so hard. I try to pre-empt it like MadB says, but I miss it most times (blame the demanding almost 4yo!).

I'm just using breast milk atm. It's hard to say if it's working as he does it quite often. Do you 'stick' to your breast pads/bra like me? I guess the Lansinoh would help there by keeping it moist.