Every so often (every few days) my son, who is currently 9 weeks old, does a weird thing to my nipples - like he's folding them over in his mouth. It's horrible! The sensation is akin to someone scratching their fingernails down a blackboard! Has anyone else experienced this? Any advice? I take him off when he does it but it doesn't seem to be working. It's like he only wants my nipple in the front of his mouth, because it's easy to prise him off when usually it's a real struggle. I don't think positioning is a problem. I'm having a bad day (plus he's got is first vaccinations this afternoon!). Thanks!