>>936129995
Grew up with a single mum who once dressed me in my older sister's knickers because I ran out of y-fronts to wear. Their shape was mostly the same, but they felt really good. I asked about wearing them again the second day despite her doing washing/drying my own clothes and instead of forcing me to wear my own stuff, she allowed me to try it out for a few more days. A week later she bought me my own knickers to wear whenever I wanted.
I still got male underwear too to wear at school (to save from embarrassment on the playground or in a changing room), but I primary wore knickers from then on and I still do to this day. Wearing boxers is actually weird for me.
My sister was always fine about it and we've even done underwear shopping together (both online and in shops).