DD2 is 18 months and still bf.
The issue is that she constantly puts her hands down my top. It is literally, I pick her up or put her on my lap, and she forages down my top. She doesn't want a feed, just to hold onto my breast. It's obviously a comfort thing. And the worst thing is, she is also rather fond of tweaking my nipple.
I find it really invasive and upsetting, to the point I have to take a deep breath not to lose my temper with her now. I wouldn't mind so much if it was occasionally, but it is all the bloody time. I sometimes find myself avoiding picking her up because I don't want another tweaking 
I have tried calmly telling her to take it out, and removing it if she doesn't, but it is no better after a million repetitions. She knows what she is doing, as sometimes when I tell her to stop, she takes it out (only to replace it 30 seconds later).
Anyone had this problem, and any tips other than polo necks?