Watching Your Spouse or Partner Get Spanked

This has been a fantasy of mine for a long time. We have this planned with a friend who will spank my wife as I watch. Has anyone else ever done this? She is nervous about it, but she is going along with it (with a few stipulations). I'm not going to participate other than be a spectator. I would like to hear from others who have engaged in this share their experiences.

Not exactly the same, but related... All my life, my best friend's family has owned the farm across the road from our farm. I'm an only child, but there were 7 kids in his family, rive boys and two girls. Growing up my parents had permission to spank any of my friends, and their parents had the same for me. Many a time I got spanked, always naked, at my friend's house in front of whoever was at home. His brothers and sisters saw me naked, and I saw all of them, both when getting spanked and the corner time before and after, and also swimming in the creek that runs through the back of their property at the bottom of the valley. When I grew up, I married my best friend's kid sister, and she said she knew she would marry me from when we were kids and she saw me naked and getting spanked, and I remember well her naked and getting spanked as a kid as well.