This was in the 60s and my friends and I were all periodically spanked.
At age 11, soon going into 6th grade, we had one or two summers when we were super bored, the six of us would go down to one of their basements .

Our game was three of us would pull down our shorts and panties and bend over to put our hands on the couch, with our bared bottoms sticking up.

Most of us already were developing with our breasts and pubic hair. So that was another fun thing to compare. But this is about our spanking game.

Three of us would spank the other three bottoms by hand. We would each give 5 spanks to see who would be Redder. The one who is the least red would stay with her bottom sticking up, and the one who was most red would get to trade places with her Spanker.

Because I am fair skinned, my red bottom turned red pretty quick. In this case, more of a dark pink. So we kept rotating until our bottoms were all the same color. Some games we did not use the hand. We may have used a ruler or hairbrush for our bottoms to see how our bottom colors compared.

Anyway, the one who got most red first after everyone had done the first complete round, got to stay out for round two and so on, until one girl was left. That one had to lay on her back on the couch and her Spanker would hold up her legs over her head for each of us to give one hard spank.
Believe it or not, the loser was the winner because she held out the longest and we each had to pay her $1.00 because she had the redder bottom.
We eventually got tired of this game and found other creative games. Especially because bottoms needed time to heal and we had to be very well behaved during that time so our parents wouldn’t see our bottoms like that. Then we would be in real trouble.

We were 4 children and I was the oldest growing up in South Africa in the 70’s and 80’s.
Spanking or rather canings were pretty much part of the daily routine in our house and school but never bare bottom.
However we regularly blackmailed each other into bare bottom hidings by threatening to tell our parents of some misdeed unless the ‘guilty’ party submit to punishment to be administered by a sibling.
I was the main culprit but my younger brother and sisters also on occasion had the opportunity to tan my naked ass with our mothers strap or cane.