One thing I realized this afternoon while I was playing peek-a-boo with my son Yamee using my shirt is that he thankfully never even attempted to twiddle my nips for comfort. I know other breastfeeding moms who still have to put up with that even after weaning their babies...
I just really nipped any attempts in the bud, so to speak, and just held their hands or tucked their arms wherever I could, so they don't develop the habit of playing with the nipple they're not suckling from.
I guess that's why I wasn't enticed to buy a rubber necklace (or are nursing necklaces made from latex? Some, I know, are made from semi-precious stones and marble-like stuff). I didn't need it.
Maybe it made a difference that my kids are boys... a part of me doesn't want my boys running around touching other women's breasts, because they're drawn to them (and I don't mean orally).