I used to go to her lingerie drawer and try things on. There were girdles, silk knickers, and I especially remember a long floaty pale blue nightgown with a gathered bodice. I would prance around my parents' bedroom posing and looking at myself in the mirror. I was too young to orgasm, but the feeling was wonderful. I would carefully put everything back exactly where I had found it. As far as I know I never got found out.
When I went to uni I searched out men's nylon briefs which were stocked by a few specialist shops.
I didn't cross-dress again until my first marriage broke up when I was 28. When she first walked out she left most of her clothes behind. I was devastated.
It was a comfort to me then, and is still a comfort to me now, 30 years later. Only difference is I thoroughly enjoy it and it's FUN.