Never wore any of my mother's things. Wore a pair of my sister's panties, but they were a pair that she didn't like and she never knew that I wore them.
I used to wear a girlfriend's clothes but not until after she knew I was a CD. She thought it was weird, but let me do it. However, I do think she might have secretly liked it because she once bought me some really nice lacy underwear which I would wear when we got intimate.
My wife once got me to wear a pair of her panties before she knew I was a CD and the rest of her clothes are too small for me, so that's never happened.
So for me, the situation of confessing about wearing somebody else's clothes has never really come up.