Re: 13 month old scratching other side
It's normal, but I doubt there's any mom out there who enjoys it! A more restrictive shirt or bra may help- it's hard to twiddle what you can't get your hands on. Otherwise, redirect, use a nursing necklace, offer a toy. If none of that works, at 13 months you can probably just put her down for a couple minutes the moment twiddling starts- she may eventually figure out that twiddling starts = nursing stops.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"