DS at 19 months is a nipple-twiddler. When he's nursing on one breast he always manages to grope his way to the other breast (no matter what I'm wearing... he once almost strangled me as I was wearing a turtle-neck ) and twiddles the other nipple. Drives me batty, besides being really uncomfortable and painful even when I'm ovulating and my nipples are sore.
I've had to grab his hand and hold it still, which means he can flail his legs freely (another hilarious habit is to reach up with his foot and try to touch my nose with his toes, popping off briefly to say "beep!" and then nursing again...
so at times I've just tried to press my forearm against the other breast while cradling his legs, thus denying him access to the oh-so-tempting-and twiddleable other nipple. It's made nursing a bit of torture at times.
I recently read a thread where a mum said that she simply asked her baby to sleep through the night and it worked (tongue-in-cheek, of course), so last night, as DS was nursing (and twiddling) away, I said to him, "DS, please don't do that, it hurts Mama."
And he pulled his hand out of my bra!
Of course it's such an ingrained habit that he soon reached in again, but I just repeated "please don't do that, it hurts Mama" and he stopped, every time!
I don't know anyone in RL who'd not laugh at me a little for being so delighted about this - most of my friends have lo's but they seem to think I'm being a hippy for breastfeeding so long... and I just had to tell someone!