Lo keeps nipping my boobs while feeding. I've got to 9 months and I'm proud if this. I intend to take him to a year, however I'm starting to struggle especially with this latest thing. He already lifts my top while feeding or pulls it down to reveal my boob. Now he's nipping me. If I try to stop him he gets really stroppy and starts crying. I have do many scratch marks on my chest and neck because of this. Tips?