BFing – Biting – OUCH! (+trialing reg. formula)

Hi. I BF my first reflux son for 13 months (until became pregnant with 2nd son). I am BFing my 2nd reflux/MPI son who turned 10 months yesterday. Here’s my problem. My first son bit me around 9 months. I sternly said — NO BITING — he cried and never bit me again. On Sat. evening, my 2nd son started biting me during his last feed of the day. He bit me maybe 10 times before I gave up. I’d sternly say NO BITING, but he’d just cry for a second and then when we’d re-start nursing, he’d bite me again. All day yesterday he bit me at every feed. He didn’t nurse at all. I gave him RTF alimentum and some pumped milk I had in the freezer (I’m down to maybe 16 oz in the freezer). He was getting RTF alimentum 1x per day so we have it in the house. I pumped, but not that much as I don’t have time to deal with a 2.5 year old, feed the 10 month old and pump each time I’d feed th 10 month old (he nurses 4 -5 times a day). He is teething (tooth 7 and 8 have broken through). My husband says tough it out and he’ll stop biting once he is done with these 2 teeth, but I’m concerned about (1) the pain from the biting and (2) that my supply will diminish as I’ll try to pump but will not pump nearly as much as he’ll eat.