S.G.
You can make a nipple hole bigger by taking a sewing needle and getting it red hot on one end by using a lighter or a match. When it's glowing red it's ready and you simply run it through the nipple hole. This expands the hole without cutting it. But if I remember right, the Playtex are a T cut so you can just take a pair of scissors and expand one or 2 of the lines just little snippets at a time. Either way, there are no pieces of nipple coming off.
Good luck!
S.