How my mom spanked me and my brother?

Growing up in 60s and 70s spanking and corporal punishment was a common affair in my home. It was mom who took charge of me and my younger brother. It was always on the bare. I was spanked till 15 or 16. Till I was 10, mom would lift up my skirt and pull my underwear down and then she would hold both my hands make me stand and turned my bottom towards her and then spanked me with her hand. As I grow older, she would tie both my hands to a pillar and beat my bottom with a stick/switch or sometimes belt. Once it all stopped I asked her why she did tie my hands. I too spanked my two sons while they were growing up. But I was too lenient on them when compared to this. I never spanked them in public.